The author(s) shown below used Federal funds provided by the U.S. 

Department of Justice and prepared the following final report: 

Document Title: Across the Universe? A Comparative Analysis 

of Violent Behavior and Radicalization Across 

Three Offender Types with Implications for 

Criminal Justice Training and Education 

Author(s): John G. Horgan, Ph.D., Paul Gill, Ph.D., Noemie 

Bouhana, Ph.D., James Silver, J.D., Ph.D., Emily 

Corner, MSc. 

Document No.: 249937

Date Received: June 2016

Award Number: 2013-ZA-BX-0002

This report has not been published by the U.S. Department of Justice. 

To provide better customer service, NCJRS has made this federally 

funded grant report available electronically. 

Opinions or points of view expressed are those 

of the author(s) and do not necessarily reflect 

the official position or policies of the U.S. 

Department of Justice.
1

This project was supported by Award No. 2013-ZA-BX-0002, awarded by the National Institute of Justice, Office of Justice 

Programs, U.S. Department of Justice. The opinions, findings, and conclusions or recommendations expressed in this 

publication are those of the authors and do not necessarily reflect those of the Department of Justice

Across the Universe? A Comparative 

Analysis of Violent Behavior and 

Radicalization Across Three Offender 

Types with Implications for Criminal 

Justice Training and Education

Final Report

 

John G. Horgan, PhD Georgia State University

Paul Gill, PhD University College, London

Noemie Bouhana, PhD University College, London

James Silver, JD, PhD Worcester State University

Emily Corner, MSc University College, London
2 

ABOUT THE REPORT 

ABOUT THE PROJECT 

The content of this report was produced by John Horgan (Principal Investigator (PI)), 

Paul Gill (Co-PI), James Silver (Project Manager), Noemie Bouhana (CoInvestigator), and Emily Corner (Research Assistant). This research is

supported by Award No. 2013-ZA-BX-0002, awarded by the National Institute

of Justice, Office of Justice Programs, U.S. Department of Justice. The

opinions, findings, and conclusions or recommendations expressed in this 

document are those of the authors and do not necessarily reflect those of the 

Department of Justice. 

This document is a research report submitted to the U.S. Department of Justice. This report has not 

been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
3 

PROJECT TEAM 

Research Team 

John Horgan – Georgia State University 

Paul Gill – University College London

James Silver – Worcester State University

Emily Corner – University College London 

Noemie Bouhana – University College London 

Data Collection Intern Team 

University of Massachusetts Lowell 

Andrew Valcourt , Autumn Calbria, Cassaundra Pellerin, Christian Nambu, 

Christopher Park, Cristiana Federico, Dijana Djuric, Gregory Johnson, Hank 

Harrington, Jackson Kellog, James Russell, Jennifer Rogers, Jessica Botero-Rua, 

Katie Kacmarek, Kelsie Ferris, Kevin Kearney, LaDonya Buchanan, Lindsey Viera, 

Matthew Febles, Melissa Mejia, Oti Achamfour, Remilekun Ogunfowara, Sean 

Rogers, Stephen Lidell, Tom Arsenault, Wesley Boudreau, Zachary Miliano 

University College London

Amy Lafferty, Jordana Clark, Linh Le, Matteo Pezella, Sarika Dewan, Sophie 

Preisendoerfer 

This document is a research report submitted to the U.S. Department of Justice. This report has not 

been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
4 

EXECUTIVE SUMMARY 

- Lone actor terrorists (sometimes referred to as ‘lone wolves’) and mass 

murderers are more often than not assumed to be distinct, with little validity 

for comparison. Yet, both engage (or attempt to engage) in largely public and 

highly publicized acts of violence and often use similar weapons. 

- Using a series of bivariate and multivariate statistical analyses, we compared

demographic, psychological and offense-related behavioral variables across 

and between 71 lone actor terrorists and 115 solo mass murderers. 

- Results indicate there is little to distinguish these offender types in terms of 

their socio-demographic profiles. However, their behaviors significantly differ 

with regards to (a) the degree to which they interact with co-conspirators (b) 

their antecedent event behaviors and (c) the degree to which they leak 

information prior to the attack. 

- The fundamental distinction between the two groups – motivation – dictates 

different actuation points for violence. By definition, mass murderers lack an 

ideology and, thus, cannot be said to engage in the decision and search activity 

involving calculations based on current political and security climates that 

characterizes the incipiency of lone actor and solo actor terrorist attacks. In 

fact, the majority of mass murderers (57%, N = 65) are concerned with 

personal feelings of having been wronged by a specific person and ultimately 

murder (or attempt to murder) the person whom they hold responsible for that 

wrong. Other mass murderers (16%, N = 18) have a grievance against a 

category of persons and attack representatives of that group (the remainder 

were either spontaneous attacks and/or any grievance is unknown). Nor do 

mass murderers typically concern themselves with post-event activity and 

strategic analysis as do lone actor and solo actor terrorists. Unlike lone and 

solo actor terrorists, some mass murders appear to be spontaneous incidents, 

arising from the physical or emotional conflicts immediately prior to the attack 

and in which the individual does not exhibit any meaningful planning 

behaviors related to the attack. While the percentage of mass murders that 

occur in these circumstances (N = 17, 15%) is relatively small, the apparent 

This document is a research report submitted to the U.S. Department of Justice. This report has not 

been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
5 

lack of predetermined intent and strategy sets at least these offenders apart 

from the terrorists in our dataset. 

- Although still exploratory in nature, our examination of the 98 mass murderers 

in our dataset who do not engage in spontaneous violence reveals that they do 

not reliably follow the same “natural history from inception to completion” of 

the attack as lone actor and solo actor terrorists. 

- As compared to the 1990-2005 period, the 2006-2013 period contains fewer 

offenders who (a) had previous military experience (b) made verbal statements 

to family/friends/wider audiences about their intent and beliefs (c) socialized 

face to face with members of a wider network (d) experienced being degraded 

or the target of an act of prejudice or unfairness (e) expressed a desire to hurt 

others (f) experienced a recent stressor. It is worth re-iterating that whilst 

prior military experience is often noted in media reports regarding the increase 

in mass murder events, the statistics suggest this factor only appears a third as 

much in the current era than it did in the 1990-2005 era which suggests that 

some so-called “risk factors” may have cohort-effects rather than having 

stable influences over time. 

- One of the major implications of comparative analyses such as this could be to 

provide guidance or a framework to those tasked with responding to such 

phenomena. Given our counter-intuitive findings on the leakage of intent, this 

may be particularly relevant in terms of early disruption of plots. An 

understanding of this complexity and the multiplicity of potential factors could 

help inform how threat assessments of particular lone actors should be carried 

out. When we talk about ‘threat’, and the related concept of risk, we need to 

consider multiple, overlapping questions including issues related to 

identification of threats (e.g., threat of what precisely?), exposure (e.g., under 

what conditions are particular offences more likely?) and management (i.e.,

which interventions are likely to be effective in terms of mitigating either risk, 

broadly speaking, or a specific threat).

- The results suggest that both offenders are very similar in terms of their 

behaviors – this in turn suggests that similar threat and risk assessment 

This document is a research report submitted to the U.S. Department of Justice. This report has not 

been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
6 

frameworks may be applicable to both types of offenders. 

This document is a research report submitted to the U.S. Department of Justice. This report has not 

been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
7 

Table of Contents 

ABOUT THE REPORT ................................................................................................ 2

PROJECT TEAM ....................................................................................................... 3

EXECUTIVE SUMMARY ............................................................................................ 4

Table of Contents .................................................................................................... 7

1. Introduction ........................................................................................................ 9

Data ............................................................................................................................ 12

2. Comparing Lone Actor Terrorists and Solo Mass Murderers .............................. 16

Introduction ................................................................................................................ 16

Method ....................................................................................................................... 16

Bivariate Analyses ....................................................................................................... 16

The Offenders .............................................................................................................. 18

Age.................................................................................................................................. 19

Gender ............................................................................................................................ 20

Education, Employment & Relationship Status ............................................................. 21

Previous Criminal History ............................................................................................. 22

Other Distal Factors ..................................................................................................... 23

Proximal Factors .......................................................................................................... 24

Attack Signaling ........................................................................................................... 26

Regression Analysis ..................................................................................................... 29

Clustering Behaviors .................................................................................................... 32

Conclusion ................................................................................................................... 34

3. Rethinking Our Conceptualizations ................................................................... 36

4. ‘Risk Factors’ and Lone Actor Violent Events: The Problems of Low Base Rates & 

Long Observational Periods .................................................................................. 45

Do ‘Risk Factors’ Change Over Time? Learning from High-Likelihood, Low-Impact Crimes

.................................................................................................................................... 46

Method ....................................................................................................................... 48

Results ......................................................................................................................... 48

Conclusion ................................................................................................................... 51

5. Routine Activity Case Studies ............................................................................ 53

Lone actor Terrorists .................................................................................................... 55

Mohammed Reza Taheri-Azar ........................................................................................ 55

Timothy McVeigh ............................................................................................................ 58

Floyd Lee Corkins ............................................................................................................ 65

Abdulhakim Mujahid Muhammad .................................................................................. 67

Eric Rudolph .................................................................................................................... 70

Scripting Lone actor Terrorist Events ............................................................................. 75

Solo Terrorists ............................................................................................................. 75

Faisal Shahzad ................................................................................................................. 75

Umar Farouk Abdulmutallab .......................................................................................... 81

Scripting Solo Terrorist Events ........................................................................................ 88

Mass Murderers .......................................................................................................... 89

Kyle Huff .......................................................................................................................... 90

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
8 

Michael McDermott ........................................................................................................ 94

Jeffrey Weise .................................................................................................................. 97

Robert Hawkins ............................................................................................................. 100

Gang Lu ......................................................................................................................... 104

Scripting Mass Murder Events ...................................................................................... 107

6. Conclusion ...................................................................................................... 111

References .......................................................................................................... 116

This document is a research report submitted to the U.S. Department of Justice. This report has not 

been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
9 

1. Introduction 

Current efforts to analyze violent extremism are hampered both by recurring 

conceptual errors and limited empirical support. To date, attempts to understand 

radicalization and/or terrorist motivation have largely tended toward generalist 

explanations that often border on explanatory fictions (Horgan, 2014). Furthermore, 

such explanations, be they theoretical models or descriptive analyses of large-n 

datasets, tend to treat group members as homogenous. Other analyses do distinguish 

offender types (e.g. lone wolf vs. al Qaeda-member) but these comparisons tend to be 

based on single case studies and devoid of crime prevention paradigms (for example,

McCauley, Moskalenko and Van Son, 2013). 

In the absence of useful comparison or, additionally, control groups (e.g. Merari, 

2010), even unashamedly empirical analyses can at best offer largely descriptive (and 

as a result, partial) account of violent extremism. As LaFree (2013:60) notes, there 

has been a nascent research trend towards the development of “specialized data sets 

on specific subsets of terrorism cases” which represents the third major development 

in the empirical study of terrorism.1

This project report seeks to contribute to this trend by engaging in an interdisciplinary and data-driven approach to understanding lone actor terrorists2

, and solo 

mass murderer attackers3. Instead of using the ‘terrorist’ or ‘offender’ as the 

dependent variable under investigation, we feel it may be more instructive to 

disaggregate and compare socio-demographic, psychological and behavioral features 

across and between these offender types. 

The discipline of criminology has largely progressed through embracing 

disaggregated methods and this project report is amongst the first to apply such 

 

1 The first being the development of international databases of terrorist attacks. The second being the 

collection of domestic international attacks. 

2 Defined as an individual who engages in ideologically-inspired violence in support of a broader 

group but absent of ties to or material support from that group. 

3

 Defined as an individual who kills four or more people in one event over a relatively short period of 

time (within 24 hours). We exclude incidents that are state sponsored, gang/organized crime related, or 

solely domestic in nature. 

This document is a research report submitted to the U.S. Department of Justice. This report has not 

been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
10

methods to the study of terrorist and or/extremist outcomes. We are aware of very 

little prior research that empirically compares terrorists and criminals in a rigorous 

manner. Cairns (1987) cites the works of Elliot and Lockhart (1980) and Curran 

(1984). The Elliot and Lockhart study compared forty juvenile terrorist offenders in 

Northern Ireland with a matched group of juvenile non-terrorist criminals. The 

terrorist sample was older, more intelligent, more socially outgoing, less likely to be 

truant from school or referred to a child psychiatrist. The Curran study focused upon a 

similar sample but required participants to self-report on 155 statements from the 

Jesness Inventory. The non-terrorist offenders scored higher on measures of 

aggression, autism, toughness and sensation seeking. Lyons and Harbinson (1986) 

compared 47 terrorists convicted of murder with 59 non-terrorist murderers. The nonterrorists were significantly more likely to be under the influence of alcohol during 

the offense and have a family history of personality disorder. Lankford (2012) 

compared the self-harming motivations and behaviors of 81 suicide terrorists and 

rampage, workplace and school shooters in the U.S. from 1990 to 2010, finding only 

superficial differences across the groups.

Our report compares offender types whose violence appears similar yet whose 

motivational structure differs. We propose that there may be significant implications 

for improving investigative practice (at a variety of levels and stages) by 

understanding the relevant distinctions between offender types. In particular, we are 

interested in the differences between lone actor terrorists and solo mass murderer 

offenders. Both engage (or attempt to engage) in largely public and highly publicized 

acts of violence and often use similar weapons. So while their outcomes often share 

multiple features, we ask if the trajectories into violence followed by the respective 

actors may be equally similar. 

Understanding the comparative nature of the development of extreme behavior with 

violent outcomes is important. From a disruption perspective, different kinds of 

guidance would effectively be tailored for offender-specific intervention policies. For 

example, what works for understanding and responding to a mass murderer may not 

necessarily be relevant for the management of a lone actor terrorist. Their behaviors, 

routines and proximity to other actors may differ substantially and as a result, give 

rise to different kinds of responses at whatever stage of the investigative process we 

This document is a research report submitted to the U.S. Department of Justice. This report has not 

been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
11

are focused, be it prevention or disruption. From a criminal justice perspective, a 

greater understanding of offender types may help with targeted treatment policies and 

risk assessments (Tracy and Kempf-Leonard, 1996). From a research perspective, it 

will ultimately help with our understanding of who takes part in particular violent 

offenses, the nature of their involvement with others and ultimately how they desist or 

disengage from violent activities (Horgan, 2009). Investigating whether particular 

variables more closely correlate with particular offender types also concerns the very 

nature of how we theorize about terrorist involvement and whether general models of 

‘radicalization’ or ‘pathways’ into terrorism are appropriate, It also highlights whether 

research on pathways into violence should be tailored for particular manifestations of 

terrorist or violent activity. Existing approaches therefore may miss the subtle 

psychological, behavioral, socio-demographic or organizational factors that may 

explain how and why some individuals are more likely to take part in particular 

violent activities than others. 

Chapter two presents the results of a series of statistical tests to distinguish the 

differences between lone actor terrorists and solo mass murderers in terms of sociodemographic characteristics and behavioral traits prior and after their violent attack. 

The results highlight that whilst some differences are apparent, their behaviors and 

characteristics are similar. 

Chapter three builds upon these findings and asks whether conceptualizing these types 

of offenders as an either/or classification is valid. It then quantifies and plots each 

offender according to the dimensional models previously theorized by Borum et al. 

(2011). 

Chapter four focuses on the conceptual and methodological problem of low base rates 

and long observational periods. 

Chapter five outlines 12 case studies, and utilizes crime scripting approaches to offer 

differing conceptual models of the violent radicalization and attack planning process 

across lone actor terrorists, solo terrorists and solo mass murderers. 

This document is a research report submitted to the U.S. Department of Justice. This report has not 

been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
12

Data 

We used open source data collection methods to develop a unique dataset that 

categorizes the socio-demographic, developmental antecedent attack, attack 

preparation and commission properties of 71 lone actor terrorists and 115 mass 

murderers. This addresses the paucity of data that has long been noted in the study of 

terrorists and mass murderers (Schmid & Jongman, 1988; Silke, 2001, 2004, 2013). 

To reduce bias in the sample, we limit our focus to United States-based offenders. 

Importantly, given the fact that lone actor terrorist attacks are still ‘black-swan’ type 

events (i.e., rare), the level of available behavioral data is consequently far higher than 

that of group-based offenders who operate on behalf of a prolific group. From 

experience of previous data-collection endeavors (e.g. Asal, et al. 2013; Gill and 

Horgan, 2013; Gill et al. 2014; Corner and Gill, 2015), it is very difficult to obtain 

much more than the very basic socio-demographic information of such group 

offenders from open sources (see Gill, 2015 for a longer discussion). Only two solo 

terrorists were identified. For the statistical comparative analyses, these two 

individuals are subsumed into the category of lone actor terrorist. We treat them as 

different offender types in the crime scripting analyses. 

Despite the palpable rise in public anxiety following events such as Columbine, 

Aurora, and Sandy Hook, the fact remains that mass murder is a rare event in the U.S 

compared to homicides with fewer fatalities. From 1976 to 2000, the percentage of 

murders that involved more than one victim ranged from 3% to 4% of homicides per 

year (Fox & Zawitz, 2003). A review of the FBI’s Supplementary Homicide Reports 

from 2000 to 2012 shows that the number of mass murders (four or more victims) was 

approximately one-tenth of one percent of all murders (excluding the 9/11 deaths). 

Nevertheless, perhaps because it occurs so infrequently but is so disturbing, there are 

few crimes that receive more news coverage than mass murder (Duwe, 2000). 

Prior to data collection, academic literature on lone actor terrorism was examined and 

from there an actor dictionary was built. This actor dictionary encompassed a list of 

offenders fitting the above criteria. Further names were also sourced through tailored 

search strings developed and applied to the LexisNexis “All English News” option. 

More individuals were also identified through the Global Terrorism Database 

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
13

developed by the National Consortium for the Study of Terrorism and Responses to 

Terrorism (START) and lists of those convicted of terrorism-related offences in the 

United Kingdom and the United States. We also examined the academic literature on 

mass murderers and built an actor dictionary, producing a list of names that fit our 

criteria (see below). Next, we identified additional offenders through databases 

created by Mother Jones, USA Today and Mayors Against Illegal Guns. Finally, we

conducted searches on Lexis/Nexis using specific terms and searched the Federal 

Bureau of Investigation’s Uniform Crime Reports for each year of the relevant time 

period to find other offenders who meet our criteria. Our final sample comprises 115 

mass murderers.

A pervasive problem with research on mass murder is the shifting definition of what 

exactly is a mass murder. Some criteria that have been considered include offender 

motive (Hempel, Meloy & Richards, 1999; Rappaport, 1998), the type of weapon used 

(Hempel et al., 1999) and the number of wounded (Dietz, 1986). Generally, these 

criteria are not relied upon in the literature, perhaps because they appear to be arbitrary. 

There is, however, general agreement that a mass murder involves multiple victims 

killed at one (or multiple but geographically close) locations over a relatively short 

period of time (Dietz, 1986: Holmes & Holmes, 1992; Hempel et al., 1999; Fox & 

Levin, 1998, 2003; Meloy & Felthous, 2004). 

Nevertheless, there is less agreement about the minimum number of victims required 

to define a murder event as “mass”. Some researchers use a threshold of two victims 

(Palermo & Ross, 1999), others use three (Dietz, 1986; Holmes & Holmes, 1992, 1994, 

2001; Peete, Padget & York, 1997), and still others use four (Duwe, 2000; Fox & Levin, 

1998, 2003). The definition used in this study is four or more victims (not including 

the offender) for the following reasons. First, four or more victims (not including the 

offender) is the demarcation line accepted by the Federal Bureau of Investigation in its 

2005 report: Serial Murder: Multi-Disciplinary Perspectives for Investigators, released 

after a meeting of experts in various fields relevant to the study of multiple homicides. 

This definition of mass murder as involving four or more fatalities was the result of 

considered reflection by the leading academics (criminologists, psychologists, forensic 

psychiatrists), and practitioners (state and federal law enforcement officials and 

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
14

prosecutors) brought together by the FBI for the specific purpose of clarifying issues 

related to serial and mass murder. 

Second, in studies such as the present one where data is collected via open source 

research methods, the number of victims is an important determinant of media coverage 

of multiple murder events. Research has suggested that media attention given to any 

mass murder is affected by certain factors, and high profile mass murders are 

significantly more likely to involve larger numbers of killed and wounded, stranger 

victims, public locations, assault weapons and workplace violence (Duwe, 2000, 2005). 

Third, practical considerations necessitated a threshold of four victims instead of three. 

A review of the FBI’s Supplementary Homicide Reports from 1976 to 1999 reveals that 

there are over three times as many cases of three victim homicides as there are four 

victim homicides (Duwe, 2004). Employing a mass murder definition of three or more 

victims would have necessitated reducing the time span of the study from 

approximately 24 years, to at most eight years. While that approach may be useful in 

future research, this study opts for the use of a greater time span which also matched 

the time span utilized in the previous lone actor terrorist data collection endeavors. 

To facilitate comparison to lone actor terrorists who, by definition, act alone and 

without direction or support, the sample includes only mass murderers who acted alone. 

In keeping with that same principle, the study also excludes state-sponsored as well as 

gang and organized crime related incidents. Also, attacks that are solely domestic are 

excluded, as these are frequently treated separately in the literature and appear to have 

a distinct genesis (Aldridge & Brown, 2003; Campbell, Glass, Sharps, Laughon, & 

Bloom, 2007; Lankford, 2012). 

 

The codebook used in this project was developed based on a review of literature on 

individuals who commit a wide range of violent and non-violent crimes, are 

victimized, and/or engage in high-risk behaviours as well as a review of other existing 

codebooks used in the construction of terrorism-related databases. The variables 

included in the codebook span socio-demographic information (e.g., age, gender, 

occupation, family characteristics, relationship status, occupation, employment, etc.), 

antecedent event behaviours (e.g., aspects of the individual’s behaviours towards 

This document is a research report submitted to the U.S. Department of Justice. This report has not 

been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
15

others and within their day-to-day routines), event specific behaviours (e.g., attack 

methods, who was targeted) and post-event behaviours and experiences (e.g., claims 

of responsibility, arrest/conviction details, etc.). Data were collected on demographic 

and background characteristics and antecedent event behaviours by examining and 

coding information contained in open source news reports, sworn affidavits and when 

possible, openly available first-hand accounts. The vast majority of sources came 

from tailored LexisNexis searches. Information was gleaned from relevant documents 

across online public record depositories such as documentcloud.org, biographies of a 

number of lone actors and all available scholarly articles. For a definition of different 

variables, see Gill et. al (2014).

Three independent coders coded each observation separately. After an observation 

was coded, the results were reconciled in two stages (coder A with coder B, and then 

coders A+B with C). In cases when three coders could not agree on particular 

variables, differences were resolved by a senior member of the research team based 

on an examination of the original sources that the coders relied upon to make their 

assessments. Such decisions factored in the comparative reliability and quality of the 

sources (e.g., reports that cover trial proceedings vs. reports issued in the immediate 

aftermath of the event) and the sources cited in the report. 

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
16

2. Comparing Lone Actor Terrorists and Solo Mass Murderers 

Introduction 

This chapter addresses whether similarities and/or dissimilarities are observable 

across lone actor terrorists and solo mass murderers and explores the implications for 

law-enforcement. Our expectation is that while the socio-demographic profiles will be 

similar between the two offender types, it is in the behavior and attack planning where 

many differences will emerge. 

Method 

The results below are based upon a series of bivariate and multivariate analyses. The 

full significant results from the bivariate analyses (chi-square, Fisher’s exact tests) are 

outlined in the next section. For the statistical analyses that follow, where possible, 

we do report or distinguish between missing data and ‘no’ answers, but it should be 

kept in mind that the likely result is that ‘no’ answers are substantially undercounted 

in the analysis. Unless otherwise stated, each of the figures reported below are of the 

whole sub-samples (n=71 lone actor terrorists and 115 mass murderers). There is 

precedent for this in previous research on attempted assassinations of public figures, 

fatal school shootings and targeted violence affecting institutions of higher education 

(Fein and Vossekuil, 1999; Vossekuil et al, 2002; Drysdale et al, 2010). 

Bivariate Analyses 

Table 2.1 outlines the behaviors where there is a significant difference between the 

lone actor terrorists (LA) and the solo mass murderers (MM). The results are split into 

three types of variables: group-related activities, antecedent attack behaviors and 

leakage-related behaviors. 

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
17

Table 2.1: Results from the Bivariate Analyses 

95% CI

Variable X2 LA % MM % p Odds Ratio Lower Upper

Group-Related Activities

Tried to Recruit Others 20.822 23.9 2.6 0.000 0.085 0.024 0.303

Interacted Face to Face 

with Members of a 

Wider Network

35.690 43.7 7.0 0.000 0.096 0.041 0.228

Interacted Virtually 

with Members of a 

Wider Network

20.822 23.9 2.6 0.000 0.085 0.024 0.303

Letters/Public 

Statements Prior to 

Attack

46.045 59.2 12.2 0.000 0.096 0.046 0.199

Recent Joined Wider 

Movement

22.458 32.4 6.1 0.000 0.135 0.054 0.337

Antecedent Attack Behaviors

University Experience 8.334 43.7 23.5 0.004 0.396 0.209 0.749

Military Experience 4.855 32.4 18.3 0.028 0.466 0.235 0.926

Military at Incident Fisher’s 8.5 0.9 0.008 0.095 0.011 0.807

Combat Experience Fisher’s 11.3 1.7 0.014

Criminal Convictions 4.028 57.5 42.6 0.045 0.543 0.299 0.988

Tipping Point 6.006 62.0 43.5 0.014 0.472 0.258 0.864

Changed Address 14.238 67.6 39.1 0.000 0.308 0.165 0.574

Live Alone 7.561 43.7 24.3 0.006 0.415 0.220 0.782

Substance Abuse 5.785 26.8 44.3 0.016 2.181 1.148 4.142

Socially Isolated 11.620 50.7 26.1 0.001 0.343 0.184 0.641

Dry Runs 31.568 33.8 3.5 0.000 0.071 0.023 0.215

Degraded 10.206 16.9 39.1 0.001 3.161 1.531 6.525

Ignored/Treated Poorly 4.742 14.1 27.8 0.029 2.352 1.075 5.147

Helpless Victim 3.298 11.3 21.7 0.069 2.188 0.927 5.163

Problems with Personal 

Relationship

21.506 26.8 61.7 0.000 4.416 2.314 8.427

Escalating Anger 3.875 40.8 27.0 0.049 0.534 0.285 1.001

Recent Stress 5.126 39.4 56.5 0.024 1.996 1.093 3.645

Chronic Stress 22.575 26.8 62.6 0.000 4.583 2.399 8.753

History with Event 

Location

44.994 29.6 79.1 0.000 9.028 4.575 17.815

Stockpile 7.285 52.1 32.2 0.007 0.436 0.237 0.801

Leakage Related Behaviors

Verbalize Intent to 

Family/Friends

13.984 59.2 31.3 0.000 0.315 0.170 0.582

Verbalize Intent to 

Wider Audience

6.021 49.3 31.3 0.014 0.469 0.255 0.862

Aware Grievance 21.241 80.3 46.1 0.000 0.210 0.105 0.419

Desire to Hurt Others 7.995 69.0 47.8 0.005 0.412 0.221 0.767

Others Involved 

Procured Weaponry

8.134 21.1 7.0 0.004 0.279 0.112 0.698

Others Aware of 

Planning

8.719 36.6 17.4 0.003 0.364 0.184 0.721

In terms of group-related activities, the results indicate that lone actor terrorists were 

significantly more likely to try to recruit others, interact face-to-face with members of 

a wider network, virtually interact with members of a wider network, produce letters 

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18

and/or public statements prior to the attack and recently join a wider movement. 

In terms of antecedent attack behaviors, lone actor terrorists were significantly more 

likely to have university experience, military experience, combat experience, criminal 

convictions, experience a tipping point in their pathway to violent extremism, change 

address prior to their attack, live alone, be socially isolated, engage in dry runs, 

demonstrate that their anger is escalating and possess a stockpile of weapons. Solo 

mass murderers, on the other hand, were significantly more likely to have a history of 

substance abuse, experience being degraded or treated poorly by others in the buildup to their violent event, experience being a helpless victim, have problems with 

personal relationships, experience both recent and chronic stress and have a history 

with the event location. 

In terms of leakage related behaviors, lone actor terrorists were significantly more 

likely to verbalize intent to commit violence to friends/family/wider audiences, have 

others aware of their grievance, express a desire to hurt others, have others involved 

in procuring weaponry and have others aware of their attack planning. This has very 

important implications for detection prior to the event itself. Without leaking intent, it 

increases the chances that intelligence or policing services will be unaware of the plot 

(supposing the recipient of the leak reports it to the relevant authorities). The 

difference in prevalence highlights the increased difficulty in detecting mass murders 

in advance of time compared to lone actor terrorist offences and this should be 

reflected in any threat management protocols going forward. The following sections 

go into these findings in greater detail. Later, we conduct a series of regressions based 

on these variable types. 

The Offenders 

Now we turn towards comparing both sets of offenders. The aim here is not to create 

an offender ‘profile’. Given the broad spectrum of motivations and ideologies across a 

low base rate of lone actor terrorists (Gill, 2015; Gill, Horgan and Deckert, 2014) 

such an endeavor is conceptually and empirically problematic and also holds little 

practical relevance for investigative purposes. Instead, our goal is to provide better 

insight into what variables we see universally across all crimes and terrorist types, and 

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19

what offender characteristics appear to be particularly prominent within one sample 

compared to the other. 

Age 

Within criminology, there is a long established relationship between age and 

offending. A number of studies (across a wide range of crimes) illustrate that as 

individuals become older, they also become less likely first time offenders. The 

chances of becoming a first time offender “ascends rapidly during adolescence, peaks 

in early adulthood and falls thereafter” (Stolzenberg and D’Alessio, 2008:66). Hirschi 

and Gottfredson (1983:552) refer to this relationship as “one of the brute facts of 

criminology” (Hirschi and Gottfredson, 1983:552). Data from Gill and Horgan’s 

(2013) study of 1240 Provisional Irish Republican Army members demonstrates a 

similar relationship (see figure 2.1). Here, the peak first-time offending years were 

between 17 and 21, followed by a slow decline until the age of 27 where there is a 

precipitous fall followed by a long slow decline. 

Figure 2.1 – Age Crime Curve of 1240 PIRA Members 

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Both the lone actor terrorist sample and the mass murderer offender sample do not 

reflect “one of the brute facts of criminology” (Hirschi and Gottfredson, 1983:552). 

There was no significant difference between the two sub-samples and the average age 

of the whole sample was 34 years. Figure 2.2 illustrates no curvilinear relationship,

with peak offending occurring in the early 20s, late 20s and mid-30s. The average 

age appears much higher than terrorist group-based studies previously highlighted. 

Florez-Morris’ (2007) sample of Colombian terrorists (across three distinct groups, 

CRS, M-19 and the EPL) averaged 20 years of age. Both Gill and Horgan’s (2013) 

sample of Provisional IRA members and Sageman’s (2004) global jihadist sample 

averaged 25 years of age. 

Figure 2.2 – Age Crime Curve of Lone Actor Terrorists and Mass Murderers 

Combined 

Gender 

Males heavily dominate both offence types. Only three females made the mass 

murderer offender dataset: in October 2006, Valerie Moore (by then an already 

convicted and released murderer) killed 12 and injured a further 31 after intentionally 

setting fire to a mattress outside the hotel room of an individual with whom she had 

recently argued. Also in 2006, Jennifer San Marco returned to her former workplace 

0

2

4

6

8

10

12

14

14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54

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21

at a Postal Service office and shot and killed six before turning the gun on herself. 

During a February 2014 tribal meeting to discuss her possible eviction, Cherie Lash 

Rhoades fired from two handguns and wielded a butcher knife, killing four. Rachelle 

“Shelley” Shannon was the only female who made the lone actor terrorist dataset. She 

shot Dr. George Tiller (who survived but was later assassinated by lone actor Scott 

Roeder) outside his abortion clinic in Kansas in 1993. 

These outliers are similarly reflected in gender representation within terrorist groups 

such as the Provisional Irish Republican Army (4.9%) and ETA (6.4%) (Gill and 

Horgan, 2013; Reinares, 2004). The wider crime literature also shows that males are 

also far more likely to engage in a wide range of violent and illegal behaviors (see 

Gill, 2015 for a full explanation). Indeed, males account for 93.2% of all sentenced 

prisoners in state or federal prisons according to a 2010 U.S. Department of Justice 

report (Guerine, Harrison, & Sabol, 2011). In effect, the relatively low preponderance 

of females in the sample is nothing extraordinary. 

Education, Employment & Relationship Status 

Of those lone actor terrorists with available data (n=48), two-thirds took part in some 

form of university education with 21% possessing an undergraduate degree as their 

highest form of educational attainment, an additional 15% holding a masters and 4% 

holding an accredited Doctoral degree. Only 10% dropped out of secondary 

education. Generally speaking, the mean education level for this offender sample is 

impressive. The mass murderers were significantly less educated. Only 24% of the 

sample had some experience of university education, with 11% finishing an 

undergraduate degree, and 4% finishing some form of graduate degree. 

However, the educational success of the lone actor terrorists did not translate into 

direct success in the job market. 38% were unemployed. 21% worked in the service or 

administrative sectors. Only 8% were active professionals. The general aggregate 

picture from the lone actor terrorist cohort is that of a well-educated sample but one 

who largely failed to translate this to real-world success. Despite the lower education 

attainment, only 28% of the mass murder offenders were unemployed, 33% worked in 

the service or administrative sectors and 5% were professionals. 

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22

There was no significant difference between the samples in terms of relationship 

status. A high percentage of both lone actors and mass murderers were single (37% 

and 43% respectively), smaller numbers were married (19% and 17%) or divorced 

(16% and 13%). 

Previous Criminal History 

In 2007, Jason Roach published a research article called ‘Those who do big bad things 

also usually do little bad things’. Roach promotes the concept of ‘self-selection’ to 

catch serious offenders. The basic idea is that serious offenders are often identified 

and captured by police after the commission of a lesser offence: “serious offenders are 

often crime versatile, committing an array of different crimes, including minor as well 

as serious offences. People who do big bad things, will not cavil at doing little bad 

things” (Roach, 2007:67). It should be no surprise therefore that much academic work 

on volume crime shows that a large predictor of future engagement with criminal and 

illicit behaviors is whether the individual has a previous history of criminal or illicit 

activities. Previous research has shown that offenders with prior convictions 

(including child molestation, robbery, or multiple probation sentences) are more 

likely to engage in a spree of homicidal offending (DeLisi, Hochstetler, Scherer, 

Purhmann, & Berg, 2008). Fein and Vossekuil’s (1999) study of individuals who took 

part in or attempted to take part in an assassination of a public figure illustrated that 

56% of the sample had one or more arrests for a non-violent offense while 20% had 

one or more arrests for a violent offense. 

When we turn to the lone actor terrorist sample, we find similarly high figures. 58% 

had a previous criminal conviction. Of this sub-sample, 59% served time in prison 

indicating the seriousness and/or prolific nature of their offending. The corresponding 

figure for previous convictions amongst the mass murderers was lower, at 43%. 

However, a higher percentage of these individuals (67%) served time for their offence 

(suggesting they are more serious previous offenders). Offences across both subsamples included non-violent activism, vehicle theft, counterfeiting, disorderly 

conduct, robbery, drink driving, concealed weapons conviction, counterfeiting, felony 

drugs convictions, assault, aggravated harassment, extortion, tax fraud, sexual assault, 

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23

lewd conduct, arson, kidnapping, child pornography possession, firearms offences, 

grand larceny, and bank robbery. We therefore see a very wide range of illegal 

activities and certainly no concentration of one crime type that we can identify as an 

escalatory “trigger” for subsequent behavior into lone actor terrorism or mass murder.

Other Distal Factors 

There are a number of other behaviors logged within both datasets that provide an 

understanding of the offender’s behavioral background. These are listed in Table 2. 

The results highlight the fact that lone actor terrorists were significantly more likely to 

be socially isolated, living alone at the time of their offense, and to have a history of 

military and combat experience. Mass murderers on the other hand were significantly 

more likely to have experienced long-term stress. Examples of this include: academic 

frustration stemming from learning disorders; difficulty maintaining employment and 

failure in business ventures; disabling injuries from automobile and work accidents; a 

range of mental health issues including depression, bi-polar disorder and posttraumatic stress disorder; an inability to establish appropriate social relationships; 

long-lasting discord in marriages and romantic relationships; and even being the main 

suspect in a double murder for over six years. 

Table 2.2 Prevalence of Distal Factors 

Variable Lone Actor 

Terrorists

Mass Murderers

Socially Isolated 51%*** 26%

History of Mental Illness 39% 48%

Lived Alone at Time of Event 44%*** 24%

Experience of Long-Term Stress 27% 63%***

History of Substance Abuse 27% 44%**

Military Experience 32%** 18%

Combat Experience 11%*** 2%

*** = p < .001, ** = p <.01, * = p < .05 

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24

Although there was no significant difference in terms of mental illness prevalence, 

Corner, Gill and Mason (2015) illustrated that the nature of the disorders themselves 

differed across actor types. Figure 2.3 presents these results. Lone actors show higher 

prevalence of psychotic disorders (those within the F20-F29 bracket of the ICD-10). 

Whereas mass murderers demonstrate higher prevalence of substance related 

disorders, major depressive disorder, personality disorders, disorders related to 

psychological development (F70-F79, F80-F89), and behavioral disorders with 

juvenile onset (F90-F98). 

Proximal Factors 

This section provides an overview of the prevalence of behaviors the individual 

engaged in very near to the terrorist event or planned event. None of these behaviors 

0.00%

2.00%

4.00%

6.00%

8.00%

10.00%

12.00%

14.00%

TBI

Drug Dependence

Drug Induced Psychosis

Schizophrenia

Schizoaffective Disorder

Delusional Disorder

Schizophreniform Disorder

Psychotic Disorder

Depression

Bipolar Disorder

Unspecified Anxiety Disorder

Dissociative Disorder

Adjustment Disorder

OCD

PTSD

Unspecified Sleep Disorder

Anorexia

Unspecified Personality Disorder

Learning Disability

ASD

Unspecified Developmental Disorder

Oppositional Defiant Disorder

ADHD

F00-

F09

F10-F19 F20-F29 F30-F39 F40-F49 F50-F59 F60-

F69

F70-

F79

F80-F89 F90-F98

Figure 2.3: Mental Disorder Prevalence across Actor Types

Mass Casualty Offender Lone-Actor

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25

are attack-related specifically, but again provide a more holistic view of the 

immediate life-situation various actors found themselves in just prior to planning their 

attack. The results again highlight the importance of short-term situational risk 

factors. Consistently across a number of variables, it appears that these short-term risk 

factors appear most commonly for mass murderers, particularly in the 6-month time 

frame prior to their eventual attack. 

Table 2.3. Prevalence of Proximal Behaviors 

Variable Occurred within 2 

Years

Occurred within 1 

Year

Occurred within 6 

Months

LA = Lone Actor

MM = Mass 

Murderer

LA = Lone Actor

MM = Mass 

Murderer

LA = Lone Actor

MM = Mass 

Murderer

Religious Beliefs 

Noticeably 

Intensified

LA - 6%

MM – 1%

*

LA – 4%

MM – 1%

LA – 3%

MM – 1%

Ideological Beliefs 

Noticeably 

Intensified

LA – 35%

MM – 1.7%

***

LA – 28%

MM – 1.7%

***

LA – 18%

MM – 1%

***

Recently 

Unemployed

LA –28%

MM – 30%

LA – 22%

MM – 28%

LA – 13%

MM – 24%

Experienced 

Being Degraded

LA - 13%

MM – 31%

**

LA - 11%

MM – 24%

*

LA - 6%

MM – 17%

*

Target of a 

Perceived Act of 

Prejudice

LA - 17%

MM – 24%

LA - 14%

MM – 17%

LA - 6%

MM – 10%

Problems with 

Personal 

Relationships

LA - 17%

MM – 40%

**

LA - 13%

MM – 37%

***

LA - 7%

MM – 25%

**

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26

Financial 

Problems

LA - 24%

MM – 24%

LA - 20%

MM – 24%

LA - 13%

MM – 19%

Elevated Level of 

Stress

LA - 32%

MM – 51%

*

LA - 27%

MM – 45%

*

LA - 17%

MM – 36%

**

*** = p < .001, ** = p <.01, * = p < .05 

Attack Signaling 

One of the most surprising behavioral trends was the extent to which the sample 

tended to leak information to others regarding their attack plan (See Table 4). Studies 

of similar actors have however found similar results. For example, Meloy et al.’s 

(2001) study of adolescent mass murderers in North America illustrated that 44% of 

the sample discussed the act of murder with at least one other person prior to the 

event itself. Also, 58% of the offenders in their study made threatening statements 

alluding to mass murder prior to the event and this was usually to a third-party 

audience. In 81% of Vossekuil et al.’s (2002) sample of U.S.-based school shooters, 

at least one other individual had known of the offender’s intentions or specific plans 

for the school attack. In 59% of the cases, more than one non-attack related person 

had prior knowledge. Unlike Meloy et al.’s study, there was a lower rate of school 

shooters (17%) who provided specific pre-event warnings. Vossekuil et al. (2002:26) 

also found that although most of the offenses were committed by individuals, in 44% 

of the cases the solo offender was “influenced by other individuals in deciding to 

mount an attack, dared or encouraged by others to attack, or both”. In some of these 

cases, others aided the solo offender in acquiring the weapon and/or ammunition. 

Finally, Fein and Vossekuil (1999) studied individuals who committed or attempted 

to commit assassinations of public figures in the United States. They illustrate that 

although specific pre-attack warnings are a rare-event, often others close to the 

offender were either aware of his/her interest in assassinations (44%), history of 

verbal/written communications about the eventual target (77%) or history of indirect, 

conditional or direct threats concerning the eventual target (63%). 

The leaking of intent is therefore a key indicator to keep in mind with regards to 

developing a strategy to counter lone actor terrorism. However, this information 

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cannot be acted upon if the recipient of the leaked information does not communicate 

with the relevant authorities. There could be clear barriers to this information being 

passed on. For example, Borum (2013:108) posits that “those with kinship bonds may 

not approve at all of the attacker’s intent, but they may feel restrained from acting 

because of love and loyalty or concern about the consequences”. Borum further 

outlines that research on such reporting mechanisms shows that factors such as the 

presence of multiple reporting channels, anonymity, accessibility, safety and 

credibility are key to successful transmission of this information. Of course, not all of 

the instances in which information is received about verbalized intent are viable 

threats or risks so instead of acting straight away, the logical next step is to engage in 

a risk assessment and look at the rest of the individual’s behaviors with regard to their 

situation, capability, motivation and opportunity to act. The results in table 4 highlight 

the fact that lone actor terrorists engage in significantly more ‘leaky’ behaviors and 

this could be for a number of reasons. Lone actor terrorists may be less likely at the 

outset to actually want to be alone in the attack. This is evidenced in the contrasting 

findings with regard to their likelihood of trying to recruit others. Political grievances 

also may tend to have a wider audience than the deeply personal and idiosyncratic 

grievances of mass murderers. Hence, the opportunities to interact and leak intent 

may also be strengthened. Another possible reason may be that lone actors may be 

more likely to attack high profile targets which may lead to a longer attack planning 

and hence more time to leak intent. This lack of planning on a subset of the mass 

murderer sample may be indicated by the large number that consumed alcohol or 

drugs prior to their attack. Finally, it may be because of the ‘lone actor terrorist 

dilemma’ depicted by Gill (2015). Without leaking intent prior to the attack, the lone 

actor terrorist’s actions may be depicted as the actions of a mad man rather than that 

of a rational terrorist. Without the ideological drivers being reported, the act cannot be 

an act of terrorism because it is ‘message-less’ for all intents and purposes.

Table 2.4. Leakage & Group-Related Activities 

Behavior Lone Actor Terrorist Mass Murderer

Other People Aware of the 

Individual's Grievance

80%*** 46%

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Other People Aware of 

Individual's Extremist Ideology

77% N/A

Made Verbal Statements to 

Friends/Family about Intent or 

Belief

59%*** 31%

Interacted Face to Face with 

Members of a Wider Network

44%*** 7%

At Least One Other Knew of 

the Individual's 

Research/Planning/Prep for an 

Attack

37%** 17%

Interacted Virtually with 

Members of a Wider Network

24%*** 3%

Received Help in Procuring 

Weaponry

21%*** 7%

Produced Public Statements 

Prior to the Event

59%*** 12%

Made a Pre-Event Warning 26% 19%

Sought Legitimization from 

Epistemic Authority Figures

10%*** 0%

Learnt Through Virtual Sources 29%*** 10%

Tried to Recruit Others 24%*** 3%

*** = p < .001, ** = p <.01, * = p < .05 

Finally, there are additional event related behaviors that produced interesting results. 

The mass murderer sample were significantly more likely to have familiarity of the 

attack location (79% vs. 30%) and this may account for why the lone actor terrorists 

were significantly more likely to engage in dry runs (34% vs. 4%). The mass 

murderers were also significantly more likely to consume drugs or alcohol just prior 

to the attack (20% vs. 4%). 

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29

Regression Analysis 

None of the above behaviors occur in isolation. The development of any of these 

individuals’ behavior typically involves the crystallization in time and space of a 

number of factors. Because of this, we conducted a series of logistic regression 

analyses.4

The variables from Table 2.1 were entered into a series of regression analyses. Tables 

2.5-2.7 outline these results. Model 1 analyses group-related behaviors using a 

logistic regression (mass murderers =1) (see table 5). The analysis showed that in 

combination, the independent variables significantly impacted upon whether the 

individual was a lone actor terrorist or a solo mass murderer (X2(5)=68.510 p<0.001). 

Individuals who carry out both face to face and virtual interactions with coideologues, and those who produced letters after the event were significantly more 

likely to be lone actor terrorists, These results are not unexpected given the 

ideological motivations of lone actor terrorists versus the personal motivations of 

mass murderers, but do underscore ways in which these different impulses to action 

may affect offenders’ willingness and/or need to interact with others both before and 

after the attack.

Table 2.5 – Logistic Regression Analysis of Group Related Behaviors 

Variable B(SE) Sig. Lower Exp(B) Upper

Recently Joined a Wider 

Group

-.431(.739) .559 .153 .650 2.763

Interacted Face to Face with 

Members of a Wider Network

-1.403(.665) .035* .067 .246 .906

Interacted Virtually with 

Members of a Wider Network

-1.848(.740) .013* .037 .158 .672

Tried to Recruit Others -1.381(.774) .074 .055 .251 1.145

Produced Letters Post-Event -2.270(.566) .000*** .034 .103 .314

 

4 For all the subsequent regression analyses, all assumptions for model were met 

(linearity of logit not relevant as all independent variables were categorical, no 

overdispersion was present), and diagnostics (including Collinearity) are presented in 

Appendix 1.

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Constant .000 4.375

Model 2 analyses antecedent-event behaviors using a logistic regression (see table 

2.6). The analysis showed that in combination, the independent variables significantly 

impacted upon whether the individual was a lone actor terrorist or a solo mass 

murderer (X2(19)=169.313 p<0.001). A number of variables were significant 

predictors of actor type. Individuals who had university experience, military 

experience, a history of criminal convictions, experienced a recent change in address, 

experienced a recent tipping point, showed evidence of social isolation, showed 

evidence of escalating anger just prior to the event, and stockpiled weapons were 

significantly more likely to be lone actor terrorists. Individuals who had a history of 

substance abuse, problems with personal relationships, experienced a recent stressor, 

experienced chronic stress, and a history with the attack location were significantly 

more likely to be solo mass murderers.

Model 3 analyses leakage related behaviors using a logistic regression (see table 2.7). 

The analysis showed that in combination, the independent variables significantly 

impacted upon whether the individual was a lone actor terrorist or a solo mass 

murderer (X2(7)=61.558 p<0.001). Only two of the variables remained significant. 

Individuals who produced letters prior to their attack, and those who had help in 

procuring weaponry for their attack were significantly more likely to be lone actor 

terrorists.

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Table 2.6 – Logistic Regression Analysis of Antecedent Event Behaviors 

Variable B(SE) Sig. Lower Exp(B) Upper

University Experience -2.836(.902) .002** .010 .059 3.44

Military Experience -3.129(.952) .001** .007 .044 .283

Criminal Conviction -3.410(.955) .000*** .005 .033 .215

Recent Address Change -2.562(.815) .002** 0.16 0.77 3.81

Tipping Point Experienced -1.724(.770) .025* .039 .178 .807

Lived Alone .618(.778) .427 .404 1.856 8.531

History of Substance Abuse 3.593(1.003) .000*** 5.085 36.328 259.515

Socially Isolated -1.807(8.72) .038* .030 .164 .907

Experienced Being 

Degraded

2.207(8.58) .010* 1.689 9.084 48.857

Experienced Having a 

Promise Broken

3.050(2.963) .303 .064 21.120 7023.44

Experienced Being Ignored -.153(1.094) .889 .101 .858 .7321

Experienced Others Not 

Caring For Them

1.720(1.017) .091 .761 5.585 41.000

Felt Helpless -.783(1.019) .442 .062 .457 3.368

Problems with Personal 

Relationships

1.877(.755) .013* 1.489 6.537 28.690

Evidence Anger was 

Escalating

-

2.964(1.035)

.004** .007 .052 .393

Experienced a Recent 

Stressor

1.880(7.67) .014* 1.457 6.552 29.474

Experienced Chronic Stress 1.398(.633) .027* 1.170 4.045 13.986

History with Attack 

Location

3.570(.861) .000*** 6.570 35.533 192.181

Stockpile of Weapons -2.475(.849) .004** .016 .084 .444

Constant 2.328(1.025) .023 10.260

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Table 2.7 – Logistic Regression Analysis of Leakage Related Behaviors 

Variable B(SE) Sig. Lower Exp(B) Upper

Produced Letters Prior to the 

Attack

-2.253(.439) .000*** .044 .105 .248

Made Verbal Statements to 

Family About Intent

-.634(.436) .146 .226 .530 1.246

Made Verbal Statements to 

Wider Audience

.556(.447) .214 .726 1.743 4.184

Others Aware of Grievance -.543(.473) .251 .230 .581 1.467

Expressed a Desire to Hurt 

Others

-.020(.423) .962 .428 .980 2.244

Other Individuals Helped 

Procure Weaponry

-1.274(.587) .030* .089 .280 .883

Other Individuals Aware of 

Attack Planning

-.293(.469) .532 .297 .746 1.871

Constant 1.881(.351) .000 6.559

Clustering Behaviors 

In this section, we utilize multidimensional scaling techniques to assess the variables’ 

relationships with one another rather than their relationship with pre-determined 

dimensions (e.g., lone actor vs. mass murderer). 

The analysis below depicts a Smallest Space Analysis based on 16 supposed risk 

factors for engaging in lone actor events, be they inspired by ideology or personal 

grievance (or often both). The output (Figure 2.4) geometrically represents the levels 

of association between variables. The closer two variables are, the more often they cooccur and the less often each occurs in the absence of the other. 

The output highlights a number of interesting findings: 

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33

1. Capability matters. Whilst much emphasis is placed upon motivations in various 

analyses, the below output highlights that capability should also be analyzed in as much 

detail. Whether the individual tried to recruit others (RECRUIT) and whether they had 

previous military experience (MILITARYEXP) are on opposite ends of the spectrum, 

meaning that they rarely co-occur. The reasons why individuals attempted to recruit 

others include issues such as not being prepared in terms of technical capability or 

individual psychology to go it alone. Military training may help negate such worries. 

2. Many do not set out to be lone actors. The right hand side of the output illustrates a 

number of behaviors related to engagement with wider activist groups. They include 

whether the individual virtually interacted with members of a wider network 

(VIRTUALINTERACTION), interacted with members of a wider network face-to-face 

(F2F), tried to recruit others (RECRUIT), and whether others were aware of attack 

planning (OTHERSAWARE). 

3. The most common co-occurring risk factors related to leakage and included whether 

the individual made verbal statements to friends and family about their intent 

(VERBALFAF), or verbal statements to wider audiences about their goals 

(VERBALWA), or grievance (AWAREGRIEVANCE). 

4. Violent extremism is not an offline vs. online dichotomy. Our observations very often 

interacted with other members of a wider network in both virtual 

(VIRTUALINTERACTION) and real-world domains (F2F). This finding is 

presumably driven by the lone actor terrorist cohort. 

5. Background factors mixed with short-term stressors are key to understanding many 

of the lone extremists. We included two variables related to recent stressors; stress 

(ELEVATEDSTRESS) and whether the individual experienced a tipping point prior to 

their violent radicalization (TIPPINGPOINT). These two proximal stressors are 

noticeably close to distal risk factors such as the experience of mental illness 

(MENTALILLNESS), substance abuse (SUBSTANCE ABUSE), previous military 

experience (MILITARYEXP), a history of criminality (CRIMINALCON) and a history 

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34

of violent behavior (PREVVIOLENCE). This is particularly noticeable when the 

group-related behaviors outlined in finding 2, appear on the opposite side of the output. 

Figure 2.4 – Multidimensional Scaling Analysis of Behavior Clustering

Conclusion 

What we see from the analysis we offer here is that lone actor terrorism and mass 

murderer attacks are (both) usually the culmination of a complex mix of personal, 

political and social drivers that crystalize at the same time to drive the individual 

down the path of violent action. Whether the violence comes to fruition is usually a 

combination of the availability and vulnerability of suitable targets that suit the heady 

mix of personal and political grievances and the individual’s capability to engage in 

an attack from both a psychological and technical capability standpoint. Many 

individual cases share a mixture of personal life circumstances coupled with an 

intensification of beliefs that later developed into the idea to engage in violence. What 

differed was how these influences were sequenced. Sometimes personal problems led 

to a susceptibility to ideological influences. Sometimes long-held ideological 

influences became intensified after the experience of personal problems. This is why 

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35

we should be wary of mono-causal ‘master narratives’ about how this process 

unfolds. The development of these behaviors is usually far more labyrinthine and 

dynamic. The chapters that follow seek to measure (a) whether, in light of these 

findings, a new continuum-based understanding of large-scale individual violent 

actors is realizable and (b) whether the temporal sequencing of these violent 

radicalization pathways differ. The conclusion considers the practical implications of 

these findings. 

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36

3. Rethinking Our Conceptualizations 

Chapter two began with the assumption that lone actor terrorists and mass murderers 

are distinct categories of offender. The subsequent analysis highlighted that, in fact, 

they share more similarities than dissimilarities. The binary classification (lone actor 

terrorist versus mass murderer) is not so easy when we drill deeper into specific cases. 

Consider the cases of Jim David Adkisson (largely considered a terrorist) and Elliot 

Rodger (largely considered a mass murderer). 

In 2008, Jim David Adkisson opened fire on a church congregation, killing two and 

injuring seven. Adkisson had a history of drug and alcohol problems and repeatedly 

lost jobs. The opening and concluding page of his four-page suicide note/claim of 

justification5outlines: “I guess you’re wondering why I did this. Well let me explain 

in detail. Over the years I’ve had some good jobs, but I always got layed [sic] off. 

Now I’m 58 years old and I can’t get a decent job. I’m told I’m ‘overqualified’, which 

is a codeword for ‘too damned old’. Like I’m expected to age gracefully into poverty. 

No thanks! I’m done...No one gets out of this world alive so I’ve chosen to skip the 

bad years of poverty. I know my life is going downhill fast from here. The future 

looks bleak. I’m sick and tired of being sick and tired. I’m absolutely fed up”. In his 

initial police interrogation, Adkisson admits to anger and depression stemming from 

his unemployed status and lack of future prospects. His food stamps were also at risk 

of being revoked, which Adkisson had only just learnt about prior to the shooting. 

Adkisson further admits he channelled this anger out on the church and its 

congregation. With these details, Adkisson appears to be like a typical solo mass 

murderer,motivated by personal grievances and life-circumstances.

However, the contents of Adkisson’s suicide note/claim of justification go into great 

detail on the political reasons for his actions. There, he calls the Democrat party an 

ally of the terrorists in the war on terror and labels liberalism “the worst problem 

America faces today”. He accuses major news outlets of being the “propaganda arm” 

of the Democrats. The note also blames liberalism for ruining the country and its 

 

5 The note can be found here http://web.knoxnews.com/pdf/021009churchmanifesto.pdf

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37

institutions “from the boy scouts up to the military, from education to religion”. The 

church he targeted is framed as a “cult”, ultra-liberal”, “a den of un-American vipers”, 

“a collection of sicko’s, weirdo’s, and homo’s”, that “embrace every pervert”. He 

refers to his actions variously as a “hate crime”, “political protest”, and a “symbolic 

killing”. He concludes the note: “So I thought I’d do something good for the country 

and kill Democrats ‘til the cops kill me...Tell the cop that killed me that I said, 

‘Thanks, I needed that.’ I have no next of kin, no living relative. If you would take my 

sorry carcass to the body farm, or donate it to science, or just throw me in the 

Tennessee River”. 

With this information, we can now depict Adkisson as an example of an individual 

whose personal life circumstances led to a series of problems that he largely blamed 

upon wider political processes which after a period of time built up to the extent that 

he decided to act violently. He chose to attack a church that he felt was a mirror 

image of the decay he saw emanating from Washington D.C. 

However, this was not just a random church. Adkisson had previous contact with this 

church. His ex-wife previously attended there. His marriage had not ended well by 

any measure. According to court documents, Adkisson had threatened to “blow” both 

of their “brains out”. With that information, the landscape of Adkisson’s motivation 

changes again. We now have an individual whose personal problems he blamed on 

the political and when he decided to act upon it found a target that reflected his 

political concerns but also housed an individual he had a previous and highly 

acrimonious relationship with. In effect, a mixture of personal and political reasons 

led to his decision to act violently in the first place, and to act in that location 

specifically. 

Similarly, Elliot Rodger developed over time a justification for killing, but his 

grievance was rooted not in a movement, but rather in an increasing frustration at his 

own social and sexual isolation. On May 23, 2014 in the California college town of 

Isla Vista, 22-year-old Rodger stabbed to death three men in his apartment and then 

went on a shooting rampage, killing two women outside of a sorority house and one 

other man, injuring 14 more before taking his own life. Again, a number of 

interrelated factors appear to have culminated in the murderous attack. According to 

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38

a New York Times article, Rodger (a) was emotionally disturbed as a youth (b) was 

deeply affected by the divorce of his parents when he was in the first grade, (c) was 

bullied and seen as an “oddball” throughout his school years (d) never had a romantic 

relationship and felt rejected by all women (e) became bitterly envious of his male 

and female peers who did have relationships, particularly sexual relationships (f) 

perceived himself to be under financial strain (g) had previously acted violently 

toward women for not paying attention to him (h) had made threats to kill people who 

aggrieved him. A detailed description by Lovett and Nagourney (2014) describes how 

before the attack, Rodger even mailed a lengthy testimonial (“My Twisted World”) 

and posted a You Tube video (“Elliot Rodger’s Retribution”) just prior to his attack. 

The testimonial read like a political manifesto, just not a political stance that has 

much resonance outside of Elliot Rodger’s world. He notes that he “expanded on the 

political and philosophical ideals I concocted when I was seventeen, and I soon 

became even more radical about them than I ever was before”. Listed amongst his 

grievances are racial minorities and inter-racial couples. The video detailed his lonely 

suffering, his rage at girls who “gave their affection and sex and love to other men but 

never to me”, and expressing his intent to punish all those who enjoyed the romantic 

and sexual success to which he aspired but never achieved (Lovett and Nagourney, 

2014). In the final view, Rodger comes out a mass murderer and not a terrorist 

because the genesis of his action is found not in a movement or ideology but rather in 

personal agony.

Both Adkisson and Rodger experienced a range of personal, financial stressors 

coupled with social, political and personal grievances. Both experienced distal risk 

factors, had made threats of violence to others, had suicidal ideations and access to 

firearms. Their violent acts were very similar. One is treated as a terrorist, the other as 

a mass murderer. Is there a better way to categorize these types of offenders?

Borum, Fein and Vossekuil (2013) outline a dimensional approach to understanding 

lone actor terrorism. They the case that instead of debating definitions, it may be more 

useful to view (a) the degree of loneness the offender exhibited (b) the degree of 

external direction the offender received and (c) the depth of their political motivation, 

as continuums. “Analyzing cases by their features, rather than by their types, might 

better aid the investigative process, particularly if each dimension is linked to a key 

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39

facet of the attack and tracked across the spectrum of attack-related activity from idea 

to action” (2013:104). They refer to these three such features as loneness, direction 

and motivation. Loneness measures independence of activity. The loneness 

continuum plots the degree to which offenders received assistance in initiating 

planning, preparing for and executing the attack. Direction measures the level of 

autonomy the lone actor displayed in decision-making. It plots the degree to which 

the offender received instruction or guidance on issues concerning whether to attack, 

what to target and the attack type to deploy. The motivation continuum plots the 

degree to which the action is ideologically or personally driven. Borum et al. (2013) 

make the case that very few offenders will be placed on the extremes of a continuum 

but are likely to be found somewhere between the polar opposites. 

We put this theorizing to the test by plotting each of our lone actor terrorists and mass 

murderers on a three-dimensional continuums space. Each offender was assigned a 

score for each of the three continuums. 

We adapted Borum et al.’s continuums slightly to make a finer distinction between 

the loneness and direction continuums. For the loneness continuum, we included 

behaviors related to the degree to which the individual had prior contact with 

members of a wider network prior to the plot’s inception as well as whether others 

were aware a plot was being developed. Basically, the loneness continuum captures 

the degree to which bystanders may have noticed something in the individual’s 

violent radicalization trajectory. We included behaviors such as whether or not the 

individual (a) raised finance for a wider movement (b) had recently joined a wider 

pressure group or movement (c) made verbal statements to others about their intent to 

commit violence (d) expressed intentions to hurt others (e) had other individuals in 

their close social network involved in violent activity for a group/cause (f) had a 

spouse involved in a wider group/cause (g) engaged in face to face interactions with 

members of a wider network (h) engaged in virtual interactions with members of a 

wider network (i) attempted to recruit others (j) was rejected from a wider 

group/movement. For each behavior carried out by the offender, they received one 

point. Those scoring high here are therefore not very lone, those scoring low are very 

lone up (until the point of plotting). 

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40

The direction continuum looks at the degree of external help/coordination/direction 

provided from the point of plot inception to the point of the attack (remember, to be 

included in this dataset they needed to carry out the attack alone). We included 

behaviors such as whether or not the individual (a) sought legitimization from 

epistemic authority figures for their attack (b) received training (c) learnt aspects of 

their attack from virtual sources (d) downloaded bomb-making manuals (e) other 

individuals procured the weaponry on their behalf (f) other individuals helped build 

the Improvised Explosive Device (IED) for them (g) others had knowledge about the 

attack planning (h) displayed evidence of command and control links. For each 

behavior carried out by the offender, they received 1.25 points. 

At one end of the motivation continuum are those individuals who are purely 

ideologically motivated. At the other end are those purely motivated out of personal 

grievances. We included behaviors such as whether they (a) directly communicated a 

stated ideology (b) wrote letters/publications espousing an ideology (c) made verbal 

statements to friends/family about their ideology (d) had other people be aware of 

their grievance (e) had other people be aware of their extremist ideology (f) consumed 

propaganda from a wider group/movement (g) claimed the attack on behalf of a 

group. The received 1.11 points if any of these behaviors were apparent. They were 

deducted 1.11 points if either of the following behaviors were apparent (a) a recent 

stressor or (b) chronic stress. The motivation scale therefore initially ran from -2.22 

(personally motivated) to 7.77 (ideologically motivated). 

We were then left with scores for each offender across each continuum. As an 

illustration, let’s return to the cases of Adkisson and Rodger which opened this 

chapter. Adkisson scored 1 on loneness, 1.25 on direction and 5.55 on motivation. 

Rodger scored 3 on loneness, 1.25 on direction and 4.44 on motivation indicated he 

was less ‘lone’ and slightly more personally motivated. At a very aggregate level, 

there were significant differences between our lone actor terrorists and mass 

murderers across all three continuums. Lone actor terrorists were significantly higher 

up each continuum 

- Motivation (M = 4.11 vs. -.2, t(106.45) = -18.745, p <.001) 

- Direction (M=1.70 vs 0.23, t(78.99) = -7.68, p < .001) 

- Loneness (M=2.97 vs. 1.16, t(100.16) = -6.25, p < .001) 

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41

In other words, on average, lone actor terrorists were less ‘lone’, more directed and 

more politically motivated. This is perhaps unsurprising given the different 

underpinnings of these two criminal offender types. However, once we plotted these 

scores on a three-dimensional space, some interesting results emerged. 

For the below visualizations, we computed direction scores to resemble the 0-10 scale 

in the other two continuums. Figure 3.1. plots all mass murderers on the three 

dimensional space. They showed little variance in terms of the loneness continuum, 

with 33% scoring 0, a further 33% scoring 1 and a further 23% scoring 2. There was 

even less variance on the direction continuum, with 80% scoring 0 and 16.5% scoring 

1. The remaining four offenders all scored 2. The motivation continuum received the 

greatest level of variance, with 42% scoring a combined figure of the two lowest 

scores, with 26% collecting scores closer toward the ideological end of the spectrum. 

Figure 3.1. Plotting Mass Murderers Across Three Dimensions 

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42

As you would expect from the comparison of means results, above, greater variation 

was apparent within the lone actor terrorists. Just under half of the offenders scored 

three or more points. A quarter scored five or more points. However, the other half of 

offenders scored similar points to 80%+ of the mass murderers (e.g. in the 0 to 2 

range). In terms of the direction continuum, 30% scored two or more points, with five 

offenders scoring more than 5. 16% however scored 0, which is what the vast 

majority of mass murderers scored. In terms of motivational continuum, 75% scored 

three or more points. The results are displayed in Figure 3.2 

Figure 3.2. Plotting Lone Actor Terrorists Across Three Dimensions 

Loneness

Motivation

Direction

2

4

6

8

10

2

4

6

8

10

2

4

6

8

10

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43

Loneness

Motivation

Direction

2

4

6

8

10

2

4

6

8

10

2

4

6

8

10

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44

Finally, Figure 3.3 includes both lone actor terrorists (blue) and mass murderers (red). 

Although there is a clear demarcation between a large number of lone actor terrorists 

and all of the mass murderers the higher up the motivation continuum, it is evident 

also that very many lone actor terrorists inhabit similar areas that the vast majority of 

mass murderers are typically plotted. So whilst many lone actor terrorists are most 

definitely a different breed than mass murderers, many of them do appear 

exceptionally similar to mass murderers in these three regards. 

Figure 3.3 Plotting Mass Murderers and Lone Actor Terrorists Across Three 

Dimensions

Loneness

Motivation

Direction

2

4

6

8

10

2

4

6

8

10

2

4

6

8

10

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45

4. ‘Risk Factors’ and Lone Actor Violent Events: The Problems of Low Base 

Rates & Long Observational Periods 

Chapters two and three outlined a series of studies related to the prevalence and 

clustering of various indicators and risk factors potentially associated with lone actor 

terrorism and mass murder events. In terms of the methodological approaches taken 

and in terms of how the variables were treated, the chapters typified the wider study 

of school shooters (Langman, 2009), mass murderers (Bowers et al, 2010), lone actor 

terrorism (Gill et al, 2014) and spree shooters (Lankford, 2013). Such studies of low 

likelihood events build on the study of risk and high-volume crimes like arson and 

stalking. Whilst the burgeoning number and rigorous quality of data-driven 

approaches is to be welcomed, a key methodological factor differentiates these two 

types of crime studies, and it is one frequently overlooked by the former. Studies of 

high-likelihood, low-impact crimes typically utilize a sample of offenders that are 

highly clustered temporally. For example, they analyze offenders from a wider cohort 

born in the same year (and often in the same town) or they analyze similar offences 

that occurred in the same year. Such studies can afford to do so simply because of the 

high volume of observable offenders. Such approaches can potentially highlight risk 

factors that are relevant to that cohort or geographic space which are essentially 

outliers and not generalizable to offenders outside of that temporal or geographic 

space. However, given the comparative ease of conducting such studies, these outlier 

risk factors can be weeded out via replication studies conducted in very different 

locations and at very different times. 

The study of risk factors associated with engaging in high-impact, low-likelihood 

violent events is afforded no such luxury because thankfully these crimes remain rare. 

Instead, these studies collect data on offenders across a large number of years. For 

example, Meloy et al. (2001) analyzed offender characteristics of 27 mass murderers 

(individuals who killed three or more in a single event) over a 41-year period. 

Hempel and Richard’s (1999) analysis of mass murderers focuses on 30 cases spread 

over 50 years. Gill (2015) analyses 111 lone actor terrorists from 1990 to 2014. 

Finally, Fein and Vossekuil (1999) conducted a behavioral analysis of 83 assassins 

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46

and (attempted) attackers over a 50-year period. Each study highlights risk factors, yet 

fails to consider whether these factors are driven by temporal-cohorts within the wider 

observation pool or are uniform across the expanses of time under consideration. We 

never know if the high prevalence of one factor in the overall sample due to it being 

universally present in a small time frame or is it distributed evenly across the time 

period. This is potentially most worrisome in those analyses where the number of 

years of study is far greater than the number of individuals analyzed. In other words, 

though the complete descriptive results may indicate a large propensity for a behavior 

to occur, a temporal analysis may indicate that the propensity for the behavior to 

occur actually decreases (or increases) over time. As a consequence, and unless this is 

specified, there may not exist the same implications for future investigations. This has 

major repercussions for how risk assessment protocols are developed going forward. 

A more useful approach is to determine which facets of offender behavior are 

increasing/decreasing across time and whether this trend (if any) is statistically 

distinguishable from random behavior. 

This chapter compares a cohort of violent lone actors (composed of lone actor 

terrorists, and solo mass murderer attackers) from 1990-2005 with a cohort from 2006 

to 2013. The latter period witnessed a step-change in the rate and intensity of lone 

actor mass violent events so a corollary to this exploration of whether risk factors 

differ across time is to try and identify factors that may help explain this recent 

increase in events. 

Do ‘Risk Factors’ Change Over Time? Learning from High-Likelihood, LowImpact Crimes 

In 1995, Kaplan lamented that studies have not demonstrated the association between 

risk factors and criminality for two different generational cohorts. Twenty years later, 

Farrington et al (2015:48) outlined that a “key issue in criminology is to what extent 

are risk factors for offending similar over time”, yet the “question has rarely been 

investigated”. As mentioned previously, the risk factor literature related to violent and 

frequent crime is typically unworried by this temporality/generalizability issue 

because the volume of such studies can distinguish between risk factors that are 

common or outliers. The alternative to such approaches is to compare similar crimes 

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47

in similar contexts, but in different temporal eras. We are aware of only four such 

studies, three of which have been published since 2013. This section briefly outlines 

these studies.

Farrington et al. (2015) investigated the extent to which a wide variety of risk factors 

can predict general offending across two generations. Utilizing the Cambridge Study 

in Delinquent Development they compared the original sample of 411 males from 

London with their children. Risk factors for both generational cohorts were positively 

correlated. Eleven risk factors were significant predictors for offending in both 

generations. They included a convicted father and mother, harsh discipline, poor 

parental supervision, a disrupted family, low family income, large family size, poor 

housing, low school attainment, daring/risk-taking and antisocial child behavior. The 

findings only distinctly differed on three factors: parental conflict, low social class 

and hyperactivity/attention problems (although this last risk factor was measured 

differently across the two generations). The risk factors were therefore generally very 

robust across generations with the author’s concluding, “most of the findings in one 

generation were remarkably replicable in the next generation” (2015:60). 

Menard and Johnson (2015) employed a similar research design to Farrington et al. 

(2015). They analyzed data from the National Youth Survey Family Study (NYSFS), 

which had an original sample of 2,360 youths aged between 11 and 17 in late 1976. 

Menard and Johnson compared the results of this original sample group with the 

sample group’s children in 2003-2004. They found similar inter-generational risk 

factor robustness in terms of delinquent peer bonding and offending. Differences 

emerged in terms of gender as a predictor between generations 1 and 2 (e.g. being a 

male is less important), while the impact of school strain (e.g. poor grades and lower 

expectations of gaining a college education) became an important predictor in the 

later generation. 

Johnson et al. (2015) utilizes the same data as Menard and Johnson (2015), but tests a 

different series of predictor variables. Seven of the nine predictors demonstrated the 

same significance scores and direction in relationship inter-generationally. The earlier 

generation was more heavily influenced by negative life events (for example parental 

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divorce/separation), whilst the later generation was more influenced by delinquent 

peer association. 

Farrington and Loeber (1999) came to similar conclusions in their comparative study 

of the 411 London males from the 1960s (mentioned above) with a replication study 

entitled the Pittsburgh Youth Study, which examined 508 males in the 1980s. The 

results indicated that the risk factors were not only temporally robust but also 

geographically robust. 

The four studies therefore illustrate that risk factors associated with general offending 

and delinquency have proven to be quite robust across generational cohorts. In the 

next section, we conduct a series of analyses to investigate whether the same holds 

true for lone actor violent events. 

Method 

We compared the prevalence of risk factors across two temporal domains within this 

combined sample of lone actor terrorists and solo mass murderers. We decided to split 

the sample from 1990-2005 and 2006-2013. This is because from 2006 onwards, there 

was a distinct scale shift in the number of actors per year: 1990-2005 averages 5 per 

year; the corresponding figure for 2006-2013 is 12.75. 

We then used bivariate analyses to compare the prevalence of socio-demographic and 

behavioral differences. Variables displaying significant differences were then entered 

into a logistic regression to illustrate which factors held the most predictive power as 

to whether they occurred within the phase 1990-2005 (0) or 2006-2013 (1).

Results 

We found no significant differences in terms of socio-demographic variables across 

the two temporal periods. This included factors such as age, education, and socioeconomic status. Table 4.1 outlines those variables with significant differences.

Table 4.1: Bivariate Comparison of Behaviors between 1990-2005 and 2006-2013

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49

95% Confidence 

Interval

Variable X2 1990-

2005 

(%)

2006-

2013

(%)

p Odds 

Ratio

Lower Upper

Military 

Experience

15.590 38.0 13.1 0.001**** 0.246 0.119 0.506

Previous 

Imprisonment

4.274 21.5 35.5 0.039*** 2.009 1.031 3.913

Verbalized Intent 

to Family

4.266 50.6 35.5 0.039*** 0.537 0.297 0.971

Verbalized Intent 

to Wider Audience

9.035 50.6 29.0 0.003*** 0.398 0.217 0.730

Others Aware of 

Grievance

9.611 72.2 49.5 0.002*** 0.379 0.204 0.705

Experienced a 

Tipping Point

12.835 65.8 39.3 0.001  0.336 0.183 0.615

Experienced being 

Degraded

9.923 43.0 21.5 0.002** * 0.362 0.191 0.688

Target of Injustice 13.246 45.6 20.6 0.001**** 0.309 0.162 0.589

Expressed Desire 

to Hurt Others

3.032 63.3 50.5 0.082* 0.591 0.326 1.070

Experienced 

Recent Stressor

4.951 59.5 43.0 0.026** 0.513 0.285 0.926

Substance Use 

Prior to Event

2.991 8.9 17.8 0.084* 2.221 0.884 5.577

Multiple Attack 

Methods

4.510 12.7 25.2 0.034** 2.329 1.053 5.151

Non-Discriminate 

Target

5.309 26.6 43.0 0.021** 2.083 1.110 3.907

Face to Face 

Interaction

9.449 31.6 13.1 0.002*** 0.325 0.156 0.678

Overall, the results indicate that very few behaviors can be solely attributable to the 

upward scale shift in lone actor terrorist and mass murder incidents in the 2006-2013 

period. Out of the vast number of behaviors tested, only five show a greater 

preponderance in the 2006-2013 era, and one is only marginally significant (substance 

use prior to attack). Perhaps it is no great surprise that offenders are now significantly 

more likely to make use of the Internet in their planning given its ubiquity in routine 

activities for the whole population but the percentage rise is still relatively small 

(17%) compared to the more than doubling of events in both time periods. The 2006-

2013 cohort is also significantly more likely to have been previously imprisoned, 

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
50

engaged in multiple attack methods (e.g. a bombing and a shooting) and targeted 

ordinary citizens rather than a political or military target for example. 

The results also indicate that the 2006-2013 period contains fewer offenders who (a) 

had previous military experience (b) made verbal statements to family/friends/wider 

audiences about their intent and beliefs (c) socialized face to face with members of a 

wider network (d) experienced being degraded or the target of an act of prejudice or 

unfairness (e) expressed a desire to hurt others (f) experienced a recent stressor. It is 

worth re-iterating that whilst prior military experience is often noted in media reports 

regarding the increase in mass murder events, the statistics suggest this factor only 

appears a third as much in the current era than it did in the 1990-2005 era which 

suggests that some so-called risk factors may have cohort-effects rather than having 

stable influences over time. 

It suggests therefore that the crystallization of risk factors noted elsewhere in our 

research has perhaps become more diffuse in the 2006-2013 period. Future research 

may also investigate whether there is a greater clustering or copycat effect in the latter 

era. 

The logistic regression shows that, in combination, the independent variables 

significantly impacted on temporal era, X2(14) = 54.965, p <0.001. The model 

correctly predicted 72.6% of responses. Specific individual variables were significant 

predictors of year of attack as shown in Table 4.2. Odds of greater than one indicate a 

positive relationship between the predictor and dependent variable. 

Those individuals with military experience were more likely to carry out an attack in 

the years 1990-2005. Individuals who utilized multiple different weapons in an attack 

were more likely to carry out the attack in the years 2006-2013. Individuals who 

interacted with like-minded members of a wider network were more likely to carry 

out an attack in the years 1990-2005.

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
51

Table 4.2: Logistic Regression of Behaviors between 1990-2005 and 2006-2013

95% CI for Odds Ratio

Variable B (SE) Significance Lower Exp (B) Upper

Military Experience -1.272(0.438) 0.004*** 0.119 0.280 0.662

Previous Imprisonment 0.616(0.407) 0.129 0.835 1.852 4.109

Verbalized Intent to Family -0.283(0.417) 0.497 0.333 0.754 1.706

Verbalized Intent to Wider 

Audience

-0.345(0.426) 0.419 0.307 0.708 1.633

Others Aware of Grievance 0.379(0.463) 0.414 0.589 1.460 3.662

Experienced a Tipping 

Point

-0.605(0.409) 0.139 0.245 0.546 1.217

Experienced being 

Degraded

-0.586(0.412) 0.155 0.248 0.557 1.248

Target of Injustice -0.586(0.412) 0.111 0.208 0.494 1.174

Expressed Desire to Hurt 

Others

-0.705(0.442) 0.595 0.369 0.808 1.771

Experienced Recent Stressor -0.408(0.382) 0.286 0.315 0.665 1.406

Substance Use Prior to 

Event

0.218(0.577) 0.705 0.402 1.244 3.851

Multiple Attack Methods 0.871(0.495) 0.079* 0.905 2.389 6.307

Non-Discriminate Target 0.442(0.398) 0.267 0.713 1.556 3.395

Face to Face Interaction -1.137(0.484) 0.019** 0.124 0.321 0.829

Constant 1.426 0.003 4.162

Note: B= regression coefficient, Exp (B)= odds ratio 

 =p<.001; ** *=p<.01; **p=<.05; *p=<.1 

Conclusion 

The results illustrate the importance of considering temporality with low-likelihood, 

high impact events such as these. Approximately 20% of the variables that were 

tested in a bivariate manner displayed demonstrably different prevalence rates across 

two eras. This has several implications. First, we should treat with caution some 

findings related to risk factors in studies of low-likelihood, high-impact events. This 

is especially the case for those studies where the years under consideration are greater 

(or even approximate to) the number of units of observation because there is likely a 

great variance within the sample. Because of this caution, studies should highlight this 

fact and draw some inferences about what variables are on the increase/decrease. 

Second, it also highlights the need for law enforcement and intelligence agencies to 

consistently update their threat assessment protocols because some factors that 

underpin risk may be dynamic in nature. Technological, societal and environmental 

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
52 

changes can open a gateway for a new generation of offenders or act as a deterrent 

and hence the risk factors associated with these types of crimes can change. Relatedly, 

it calls for the need to continuous and systematic data collection procedures. Finally, 

this finding might necessitate moving away from examining risk factors in isolation. 

Instead, perhaps we should look at how factors cluster, sequence and crystalize and 

whether some risk factors act as substitutes in the absence of others (e.g. does the 

Internet replace the need for face-to-face interaction with members of a wider 

network). Through such endeavors we may come to realize a mechanism-based 

approach to understanding the factors that may signal low-likelihood, high-impact 

attacks. 

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
53

5. Routine Activity Case Studies 

Whilst chapter four was interested in whether the prevalence of risk factors and 

indicators changed over time, this chapter is interested in a different aspect of 

temporality and risk. More specifically, it is interested in how pre-attack behaviours 

are sequenced temporally within specific cases. This chapter draws heavily from 

established conceptual frameworks such as Situational Crime Prevention and Routine 

Activity Theory, in order to understand the behaviors that have underpinned previous 

successfully executed lone actor terrorist events. As noted by Horgan (2005:109), it is 

useful to view each terrorist offence as comprising of a series of stages “almost with a 

natural history from inception to completion.” Through such a process, it may be 

possible to formulate phase-specific intervention strategies that seek to deter and 

disrupt future lone actor terrorist plots. In order to illustrate the applicability of 

routine activity theory to understanding terrorist events, this report provides five 

routine activity analyses of lone actor terrorist events. 

Situational crime prevention (SCP) focuses upon crime events rather than criminality 

(for a full exploration of SCP in relation to terrorism see Clarke and Newman, 2006 

and Freilich and Newman, 2009). Rather than focusing on individual characteristics 

of the criminal, situational crime prevention attempts to understand the how and what

of crime: from an analysis of the offender to a greater consideration of the social and 

behavioral qualities of the offense. Though later analyses reduced the more overt 

emphasis on rational choice theory, such perspectives view offenders as a rational 

decision maker who evaluates the costs and benefit of committing or disregarding the 

crime (Carroll & Weaver, 1986; Cornish & Clarke, 1986). It has a specific focus upon 

the ‘near causes’ of crime, the situational aspects that make a crime more likely to 

occur or a potential victim more likely to be victimized. Opportunity therefore is seen 

to be an important cause of crimes and a focus for prevention. The attractiveness of 

SCP is that opportunity is often more malleable than an offender’s internal 

disposition. We see SCP every day in relation to counter-terrorism, including target 

hardening of key buildings, the West Bank barrier, making fertilizer inert and 

therefore no use in the development of HME and airport security. All of these 

measures are in place to reduce the likelihood of a terrorist attack, not to prevent or 

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
54

disrupt the adoption of extremist ideologies or to alleviate perceived grievances. It is 

about the controlling the process of how terrorist attacks may be executed, rather than 

ameliorating the drivers behind why the attack is being planned in the first place. 

Rather than focusing upon identifiers of the individual’s radicalization or general 

intelligence capabilities or potential to engage in terrorist activity, SCP approaches 

are much more interested in factors such as the routine decisions that underpin the 

actual act of violence. 

Using the framework outlined in Horgan (2005), each of five lone actor case studies 

and two solo terrorist case studies below is disaggregated into four specific stages; (a) 

decision and search activity, (b) preparation, (c) event execution, and (d) post-event 

activity and strategic analysis. The decision and search activity phase includes 

endeavors such as target selection. Targeting is not a random exercise, but rather is 

usually the result of careful deliberation and can be affected by contemporary political 

and security climates as well as individual capabilities (Horgan, 2005:111). 

The preparation phase addresses the operational, logistical and organizational issues 

affecting the violent event. Whereas the decision phase sets a broad strategic agenda, 

the preparation phase covers tactical concerns. Choosing the correct tactic for 

particular operations may be influenced by a number of issues, including 

technological feasibility, cost-effectiveness, deterrent value, the post-event image of 

the individual and his/her motives to wider constituents and supporters, the dangers of 

unwanted results (e.g. extreme repression by counter-terrorists or the possibility of the 

wrong people being killed) and the ability to overcome security measures (Dolnik and 

Bhattacharjee, 2002). The direct manifestation of violence may be a function of the 

individual’s ability to procure or develop different types of weaponry or explosives. 

From a logistics standpoint, this phase usually sees organizational decision makers 

choosing individual(s) with the specific skillsets and experience to engage in the 

event and equipping the individual(s) with the weaponry to do so. With lone actor 

terrorists, however, the preparation phase may look different because they cannot rely 

upon routine activities that may be perfected by groups over time or a terrorist 

group’s network of specialized talent. Surveillance of targets, building a bomb, testing 

the device, procuring weaponry and concealing or hiding physical evidence also fall 

within this phase. If present, these activities illustrate not only premeditation, but also 

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
55

other facets that concern the temporal and sequential flow of the preparation of a 

terrorist attack. 

The event execution stage is the sole phase that the terrorist plays out in public. It may 

involve a number of discrete events, such as maintaining security pre-event (e.g. 

priming an IED in secrecy). Other events include the transport of the individual 

and/or IED to the location of the planned attack, or in the case of a shooting attack, 

storage of the offending weapon post-attack. It also includes aspects of decisionmaking that concern the time of day to commit the offence and considerations of risk 

and opportunity in the commissioning of a terrorist offence. 

The final phase of post-event activity and strategic analysis includes ensuring that the 

lone actor can escape after the event without being arrested or killed as well as 

conducting a review of the whole attack. The adaptations present in follow-up attacks 

may reflect aspects of the offender’s strategic analysis. 

The case studies elaborated upon below include the attacks attributed to five lone 

actor terrorists, five mass murderers and two solo terrorists. These cases represent a 

good mixture of bombings, shootings and alternative attack types. They also represent 

a good spread of al-Qaeda inspired, left-wing and right-wing causes. 

Lone actor Terrorists 

Mohammed Reza Taheri-Azar 

On March 3rd, 2006, Taheri-Azar attempted to ‘run over’ students attending 

University of North Carolina (UNC) – Chapel Hill with a vehicle. In total, he injured 

nine. There were no fatalities. 

Decision and Search Activity Stage 

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
56

Taheri-Azar’s decision to turn to violence seems largely a response to U.S. foreign 

policy and developed over the course of two years. His letter of responsibility6

claimed that “due to the killing of believing men and women under the direction of 

the United States government, I have decided to take advantage of my presence on 

United States soil...to take the lives of as many Americans and American 

sympathizers as I can in order to punish the United States for their immoral actions 

around the world”. He cited religious justification for his actions: “In the Qur’an, 

Allah states that the believing men and women have permission to murder anyone 

responsible for the killing of other believing men and women. I know that the Qur’an 

is a legitimate and authoritative holy scripture since it is completely validated by 

modern science and also mathematically encoded with the number 19 beyond human 

ability. After extensive contemplation and reflection, I have made the decision to 

exercise the right of violent retaliation that Allah has given me to the fullest extent to 

which I am capable at present”. Although Taheri-Azar did not manage to cause any 

fatalities through his attack, according to his letter of responsibility his intention was 

to “murder citizens and residents of the United States of America...by running them 

over with my automobile and stabbing them with a knife if the opportunities are 

presented to me by Allah”.

Preparation Stage 

Taheri-Azar began his preparations for the eventual attack two months prior to the 

attack. He initially wanted to join the U.S. military in order to use their weapons 

against a U.S. target. In a letter to a local media outlet following his arrest he stated, 

“ideally...I wanted to fly an airplane over Washington, D.C. and drop a nuclear bomb 

on the city”. As a part of this plan, he allegedly twice met Army recruiters at his 

office and applied to a number of clinical psychology graduate schools to prepare for 

a position as a fighter pilot. Within a month, this plan was abandoned. 

 

6

 Taheri-Azar left this letter in his apartment for police to find. The contents of which are widely 

available online. 

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
57

By February of 2006, his second plan involved a shooting attack inside the Lenoir 

Dining Hall at the UNC – Chapel Hill campus. Taheri-Azar provides two different 

accounts of why this plan was abandoned. In his letter of responsibility he states that 

he applied for a permit for a handgun but “the process of receiving a permit for a 

handgun in this city is highly restricted and out of my reach at the present, most likely 

due to my foreign nationality”. In a letter to local media after his arrest, however, 

Taheri-Azar states that although he visited a gun store in Raleigh, North Carolina, and 

obtained the necessary application documents for a gun permit from the Orange 

County Sheriff’s Department in Hillsborough, he changed his mind “about attacking 

with a gun because they seem to jam very easily,” or “malfunction and acquiring one 

would have attracted attention to me from the FBI in all likelihood”.

Taheri-Azar finally decided to engage in a vehicular assault “by running over several 

people in a concentrated target zone”. He also acquired two cans of pepper spray, a 

five-inch knife, and viewed Navy Seals training videos. All of these actions were 

geared towards aiding Taheri-Azar in the case of a physical confrontation 

immediately following the vehicular assault. 

Taheri-Azar decided to attack students at the University of North Carolina because it 

was close to his home. He was also familiar with the location—he graduated from 

UNC the previous December. Taheri-Azar also chose to time his attack to coincide 

with lunch in order to maximize the number of potential fatalities and injuries. His 

letter of responsibility claimed that, “I have chosen the particular location on the 

University campus as my target since I know there is a high likelihood that I will kill 

several people before being killed myself or jailed and sent to prison if Allah wills”.

Shortly before the attack, Taheri-Azar penned a letter claiming responsibility for the 

attacks. The day before the attack itself, Taheri-Azar rented a Jeep Cherokee for the 

specific purpose of using it in the attack. He chose this vehicle because it “runs things 

over and keeps going”.

Event Execution Stage 

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

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58

Between 11:30am and 11:53am, Taheri-Azar left his apartment and drove toward 

campus. At 11:53am Taheri-Azaar drove the rented Jeep Cherokee onto UNC Chapel 

Hill’s campus. He drove toward “The Pit”, a student hub, and accelerated aiming to 

hit nearby students. After his first attempt, he made a 90-degree turn around the 

dining hall and proceeded to try to assault more students. Taheri-Azar drove two more 

miles, near the University Mall, and then phoned a police dispatcher and turned 

himself in. Later, Taheri-Azar stated that he turned himself in “to assure the world 

that I wasn’t some insane person who went on a killing rampage suddenly”. 

Post-Event Activity and Strategic Analysis

Overall, Taheri-Azar was disappointed in the attack’s outcome. He stated 

disappointment that “there weren’t more people in the area”. There is little other 

publicly available information on how Taheri-Azar analyzed his event after the fact. 

 

Timothy McVeigh 

Executed by Timothy James McVeigh, on April 19th 1995, the Oklahoma City 

Bombing killed 168 people and injured over 500. This remained the deadliest terrorist 

act on American soil until the events of September 11th, 2001. 

Decision and Search Activity Stage 

McVeigh had a long-standing interest in firearms. Trained to shoot by his grandfather 

from an early age, McVeigh would later consume many gun-related publications, and 

frequented military stores and gun shows talking to others about weaponry and gun 

rights. Over time, he became gradually more immersed in the survivalist movement 

and radical right-wing literature. He read The Turner Diaries7 dozens of times, 

cajoled others into reading it and began to adopt its message. 

 

7

 The day of the bombing, McVeigh was arrested. Inside his getaway vehicle, officers found an envelope 

with slips of paper McVeigh had clipped from books and newspapers. One such slip of paper contained 

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
59

In May 1988, McVeigh decided to join the army and participated in U.S. Army basic 

training at Fort Benning, Georgia. There, McVeigh formed a close bond with two of 

his later co-conspirators in the attack at Oklahoma City: Terry Nichols and Michael J. 

Fortier. McVeigh and Nichols, in particular, withdrew from others in their unit. 

McVeigh’s interest in survivalism continued during his time in the army. After being 

transferred (alongside Nichols and Fortier) to Fort Riley, Kansas, McVeigh rented a 

storage unit which he stocked with 100 gallons of fresh water, weaponry, 

ammunition, rations and other supplies. 

McVeigh was deployed during Operation Desert Storm. In battle he killed two Iraqi 

soldiers. In later interviews, McVeigh suggested these killings contributed to his 

suffering from post-traumatic stress. The underlying reasons behind the war and the 

depth of power asymmetry in the battle itself bothered him. He also became 

convinced the United Nations was planning to take over the world. Upon returning 

from Operation Desert Storm, McVeigh became a decorated soldier (Bronze Star, the 

Army Achievement Medal, the Southwest Asia Service Medal and the Kuwait 

Liberation Medal). He discharged from the Army in 1991, disillusioned by his failure 

to join the Army’s Special Forces. This in turn led to a growing dislike of the U.S. 

government. After being discharged, McVeigh became increasingly paranoid that the 

government intended to take away his rights, especially the right to bear arms. 

McVeigh’s anger toward the government increased following the FBI siege at Ruby 

Ridge during the summer of 1992, and grew further during the standoff between the 

U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) and the Branch 

Davidians in Waco, Texas (an event McVeigh drove to and witnessed first-hand). 

One month after witnessing the fatal raid and fire at Waco (alongside Nichols), 

McVeigh told Fortier and his wife it was time to act violently against the government. 

Prior to the bombing, McVeigh corresponded with a Michigan woman who made the 

letters available to the FBI after the bombing. One letter reads: 

 

a paragraph from the Turner Diaries that read “The real value of our attacks today lies in the 

psychological impact, not in the immediate casualties.”

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

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60

The people of this nation should have flocked to Waco with their guns and 

opened fire on the bastards! The streets of Waco should have run red with the 

blood of the tyrants, oppressors and traitors that have slaughtered our people. 

Every person responsible for this massacre deserves nothing less than to die. If 

we want to live in peace, then sometimes we must go to war...If this is too 

extreme for you, then bow down, lick the hand of your master like a willing, 

complacent whore and shut your mouth. Take whatever is dealt to you and 

your children and do not dare to complain to me about your fate. I do not have 

the patience to listen to the whining of cowards. There will be future 

massacres because we allow them to occur (cited in Kaplan, 1997:93) 

At McVeigh’s trial, the prosecution’s opening statement outlined that “Waco really 

sparked his anger; and as time passed, he became more and more and more outraged 

at the government, which he held responsible for the deaths....And he told people that 

the federal government had intentionally murdered people at Waco....He described 

the incident as the government’s declaration of war against the American people. He 

wrote letters declaring that the government had drawn... ‘first blood’... at Waco; and 

he predicted there would be a violent revolution against the American government. As 

he put it, blood would flow in the streets.” While on death row, McVeigh confirmed 

the prosecution’s arguments. In a letter to Fox News Correspondent Rita Cosby, 

McVeigh explains that “foremost, the bombing was a retaliatory strike, a counter 

attack, for the cumulative raids (and subsequent violence and damage) that federal 

agents had participated in over the preceding years (including, but not limited to 

Waco)....This bombing was also meant as a pre-emptive (or proactive) strike against 

these forces and their command and control centers within the federal building.” In a 

separate letter shown to the Observer newspaper, McVeigh stated further that when 

the “branches of government concluded that the federal government had done nothing 

fundamentally wrong during the raid...the system not only failed the victims who 

died during the siege but also failed the citizens of this country. This failure in effect 

left the door open for more Wacos.” He then “reached the decision to go on the 

offensive – to put a check on government abuse of power, where others had failed in 

stopping the federal juggernaut running amok....Borrowing a page from U.S. foreign 

policy, I decided to send a message to a government that was becoming increasingly 

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
61

hostile, by bombing a government building and the government employees within that 

building who represent that government.” 

Preparation Stage 

McVeigh’s plan required more than 5,000 pounds of ammonium nitrate fertilizer, 

approximately 1,200 pounds of nitro methane racing fuel, 350 pounds of Tovex, and 

16 55-gallon drums; this contributed to a total of 7,000 pounds. McVeigh realized this 

was far too much to assemble on his own, so he persuaded Fortier and Nichols to help 

him. At some point, McVeigh and Nichols experimented with smaller explosives on 

Nichols’ farm in Michigan. Much of McVeigh’s knowledge came from a mail order 

bomb-making manual entitled Home Made C4, which he purchased in the Spring of 

1993. According to the prosecution, “This book provides essentially a step-by-step 

recipe as to how to put together your own fertilizer fuel-based bomb. And the book 

even provides helpful hints as to where to acquire the various ingredients, the 

components.” The locations where McVeigh eventually purchased ammonium nitrate 

fertilizer and nitro methane were both suggested in this book. 

On September 30th, 1994, McVeigh and Nichols purchased a ton of ammonium nitrate 

from the McPherson branch of the Mid-Kansas Co-op using the names “Mike 

Havens” and “Terry Havens.” They needed two tons but feared such a large purchase 

would create suspicion. On October 2nd, McVeigh and Nichols stole explosives from 

the Martin Marietta Aggregates Rock Quarry in Kansas, near Nichols’ home. In total, 

they stole more than 500 electric blasting caps, seven cases of Tovex explosives 

(which would later serve as a booster to help ignite the IED’s main charge), and 80 

spools of shock tube, or ignition cord.8 Using his real name, McVeigh rented a storage 

locker in Kingman, Arizona on October 4th, 1994 for the stolen explosives. This was 

largely funded through McVeigh’s actions on the gun show circuit, where he sold 

anti-government T-shirts, hats, bumper stickers, and guns (often illegally). On 

October 18th, Nichols bought the second ton of ammonium nitrate using the same 

 

8McVeigh later cut the electric blasting caps from the plan because he felt the risk of static electricity 

accidentally setting off the bomb was too high.

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
62

pseudonym at the same store as the September 30th purchase. The ammonium nitrate 

was then kept at a rented storage unit in Herington, Kansas. 

Originally, McVeigh wanted to use anhydrous hydrazine, a potent rocket fuel, to mix 

with the ammonium nitrate fertilizer. After making several calls to chemical 

companies using a phone card under the alias Daryl Bridges, McVeigh was unable to 

find a sufficient supply of anhydrous hydrazine at an affordable price. Realizing he 

could use a different chemical, McVeigh changed his plan to nitro methane, a motorracing fuel. On October 21st, McVeigh attended a drag race in Dallas, Texas. There he 

met with Racing Fuels employee Tim Chambers, and asked for fuel so that he and his 

friends could ride motorcycles back home. McVeigh purchased three fifty-five-gallon 

drums of nitro methane for between $925 and $2,775 (dependent upon which source 

is used). 

On November 5th, 1994, McVeigh convinced Terry Nichols to rob a gun dealer in 

Arkansas who had once been a friend of McVeigh. Nichols stole an estimated 

$60,000 in valuables and weapons from Roger Moore, justified by McVeigh as 

capital for the bomb expenses. Nichols stored the stolen guns in a locker in Council 

Grove, Kansas. Heavily influence by the attack on the J. Edgar Hoover FBI building 

in Earl Turner’s The Turner Diaries, McVeigh decided to bomb a government 

building. Unlike Turner’s location in Washington DC, McVeigh wanted to hit the 

heartland of America. His initial list included possible targets in Arkansas, Missouri, 

Oklahoma, Arizona, and Texas. Ultimately, he decided on the Alfred P. Murrah 

Federal Building in Oklahoma City because he understood that it held offices for the 

ATF, Drug Enforcement Administration, and Secret Service, thereby providing 

maximum federal government causalities. Additionally he believed the U-shaped 

glass building would be easily damaged with a bomb placed inside the “U.” On 

December 15th, McVeigh and Fortier set out to Kansas to pick up the stolen guns from 

the locker in Council Grove. On the way there, they drove through Oklahoma City to 

scope out the Murrah building and surrounding area for suitable locations for the 

getaway car. 

Now that McVeigh had chosen a location, he needed to choose a day. April 19th was 

chosen for two reasons. First and foremost, it was exactly two years to the day after 

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
63

the tragic incident at Waco. Secondly, it was exactly 220 years after the “shot heard 

round the world” at the Battle of Lexington and Concord, the first military battle 

between the Patriots and the Loyalists in the American Revolutionary War. 

McVeigh needed a fake drivers license to rent the Ryder truck, which Michael 

Fortier’s wife, Lori Fortier, helped him laminate. The alias on the license was Robert 

D. Kling, born April 19, 1972. On April 14, 1995 around 4pm, McVeigh checked into 

the Dreamland Motel in Junction City, Kansas; he used his real name but gave the 

Nichols’ farm as his address. Since McVeigh was having problems with his current 

Pontiac station wagon, he decided to purchase a new getaway car. McVeigh 

purchased a 1977 Mercury Marquis from Tom Manning at the Firestone Service 

Center for $250 in Junction City, Kansas. McVeigh left Nichols’ home address and 

telephone number on the bill. McVeigh then used his phone card to reserve a twentyfoot Ryder truck from Elliot’s Truck Agency. During the phone call, McVeigh stated 

that he needed a vehicle capable of carrying 5,000 pounds. He used the alias “Bob 

Kling” for the one-way rental to Omaha, Nebraska. On April 15th, McVeigh 

completed the requisite paperwork for his truck rental and paid $280.32 in cash. He 

did not buy insurance. On April 16th, Nichols drove to Oklahoma City to meet 

McVeigh and help him with the getaway car. McVeigh parked the car in an alley very 

close to the Murrah Building and placed a sign that said, “Not abandoned. Please do 

not tow. Will move by April 23 (needs battery and cable).” Then McVeigh rode with 

Nichols back to Kansas. On April 17th, McVeigh picked up the Ryder truck at 

4:20pm, and returned to the motel in Junction City. 

On April 18th at 9am, McVeigh drove the truck to the storage unit at Geary Lake, 

Kansas, where he met Nichols. There the two men set to work creating the bomb. 

They mixed the nitro methane with each of the fifty-pound bags of ammonium nitrate 

fertilizer in the 55-gallon drums, using a bathroom scale for measuring. McVeigh 

placed the barrels in a “T” configuration so that he would not break an axle or flip the 

truck over. Once everything was mixed, McVeigh began working on the dual-fuse 

system. He drilled two sets of holes through the cab and the cargo box. Then he ran 

plastic fish-plank tubing through the holes, creating a two-minute fuse and a fiveminute fuse as backup. At the end of each fuse, he placed non-electric blasting caps. 

He also placed blasting caps onto two lines of shock tube so that when the caps 

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
64

exploded they would instantly spark the Tovex, which was placed in the center drum 

at the intersection of the T. The bomb took over three hours to construct. At one point, 

work had to stop because there were passersby. McVeigh then made his way to 

Oklahoma City, disposing of the clothes he wore while mixing the explosives along 

the way. He stayed overnight in a roadside motel. 

Event Execution Stage 

The bombing occurred the following morning, April 19th. The original plan was for 

the bomb to detonate at 11am. On the morning of the bombing, McVeigh decided that 

waiting that long was too risky, so he moved the time forward to 9am. McVeigh felt 

that by 9am, there would be a requisite number of bystanders who could be killed in 

the bombing. McVeigh’s intention to maximize the number of killings came through 

in his alleged statement to his defense attorneys that he “would not have gotten the 

point across to the government” without a heavy casualty toll. At 7am, he left the 

motel where he had stayed overnight. He entered Oklahoma City at approximately 

8:50am. Shortly after, he pulled his truck to the side to ignite the five-minute fuse. A 

block from the Murrah building, he stopped at a traffic light and lit the two-minute 

fuse. He accelerated slowly, fearing that sudden movement would prematurely 

detonate the bomb. The front parking area of the Murrah building was empty so he 

parked in front of the building, checked the fuses, locked the truck, and walked away. 

McVeigh walked about 150 yards before he felt the explosion. The explosion created 

a crater twenty feet wide and eight feet deep. The bombing killed a total of 168 

people: 163 were inside the building during the explosion. At least 500 people were 

injured. 

Post-Event Activity and Strategic Analysis 

McVeigh made it to the Mercury Marquis and was on the road by 9:10am, eight 

minutes after the bombing. At approximately 10:20am, McVeigh was pulled over 80 

miles north of the bombing by trooper Charles Hanger for driving without a license 

plate. Hanger searched the car and arrested McVeigh for carrying an unregistered 

gun. McVeigh was held at the Noble County Jail in Perry, Oklahoma. Meanwhile, the 

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
65

police had found the vehicle ID number from the Ryder truck’s axle and traced it back 

to Robert Kling. Two days later, McVeigh was transferred to federal custody on 

federal bombing charges. 

There is very little evidence of McVeigh’s post-event strategic analysis. McVeigh’s 

published letters, to a large extent, do not go into much detail about this issue. 

Operationally, he viewed the bombing as successful. Strategically, he was unsure of 

the long-lasting impact of the bombing. McVeigh felt that he left his fellow 

Americans with “the choice to try to learn from me or...choose to remain ignorant, 

and suffer the consequences.”

Floyd Lee Corkins 

On August 15th 2012, Corkins entered the offices of the conservative lobbying group, 

the Family Research Council (FRC) with the intention of “killing as many people as I 

could”.9 Corkins managed to injure a security guard before being overpowered and 

held at gun-point until the police arrived. A list found on Corkins suggested he also 

planned to target three other social conservative advocacy groups. 

Decision and Search Activity Stage 

The government’s sentencing memorandum highlights that Corkins acknowledged 

that he wanted to engage in violent activism for a long time. His parents told the FBI 

that he “has strong opinions with respect to those he believes do not treat 

homosexuals in a fair manner”. It is also known that Corkins suffered with mental 

health issues (including major depressive disorders and psychotic features) throughout 

his adult life. Six months prior to his violent action, Corkins voluntarily committed 

himself to a mental hospital because he suffered from hallucinations and “thoughts of 

killing his parents and conservative right-wing Christians”. He left a month later and 

continued counseling and medication. This is not to suggest however that there is a 

 

9 Cited in the government’s sentencing memorandum - 

http://msnbcmedia.msn.com/i/MSNBC/Sections/NEWS/z-pdfarchive/20130919_Corkins_Sentencing.pdf 

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
66

clear link between this illness and his decision to engage in violence. There are also 

no publicly available details on what helped transition Corkins from years of thinking 

about conducting violence, to actually preparing a violent act. 

Preparation Stage 

Floyd Lee Corkins originally planned to conduct a bombing attack but told police he 

“didn’t have the patience for it”. The vast majority of planning and preparation 

occurred in the week prior to the attempted attack. On August 7th, while browsing 

online Corkins identified Blue Ridge Arsenal in Chantilly, Virginia as a suitable 

location to purchase firearms. On August 9th, Corkins perused for firearms at the Blue 

Ridge Arsenal. The following day he returned and purchased a semi-automatic pistol 

and received two-hours of free firearms training. On August 12th, he visited the 

Southern Poverty Law Center’s website and identified the FRC as being anti-gay. He 

also visited the websites of the FRC and the other three advocacy groups. The FRC’s 

website states that its mission is to “shape the public debate and formulate public 

policy that values human life and upholds the institutions of marriage and the family”. 

He then printed MapQuest and Google map directions to the FRC and one of the other 

groups. Upon his later arrest Corkins made various statements like “I don’t like the 

organization and what it stands for” and “I don’t like these people, and I don’t like 

what they stand for”. On August 13th, he rehearsed the journey to the FRC. In his own 

words, he was “basically tying to go over exactly what I was gonna do” on the day of 

the attack. He managed to access the lobby of their office by telling the receptionist 

he was there to meet an FRC employee and provided a fake name. The receptionist 

checked the employee directory, failed to find someone with the provided name, 

informed Corkins and he, in turn, exited the lobby. On August 14th, Corkins visited a 

branch of Chick-fil-A and bought fifteen chicken sandwiches. He intended to smear 

these sandwiches in the face of his victims “to make a statement against the people 

who work in that building...and with their stance against gay rights and Chick-fil-A. 

They endorse Chick-fil-A and also Chick-fil-A came out against gay marriage so I 

was going to use that as a statement”. A Chick-fil-A executive, two months earlier, 

had expressed his opposition to same-sex marriage. Later that day, Corkins purchased 

a black backpack at K-mart that was eventually used to conceal his firearm and 

ammunition on the day of the attack. On the evening of August 14th, Corkins returned 

to the Blue Ridge Arsenal and purchased and took part in another two hours of 

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
67

firearms training with the weapon he purchased days earlier. Later that night, he 

loaded three magazines for the violent event he planned to conduct the following day. 

Event Execution Stage 

On the morning of August 15th, Corkins drove his family’s car from his hometown of 

Herndon, Virginia to the East Falls Church Metro Station. There, he took the Metro 

into the District of Columbia. After departing the Gallery Place Metro stop, he loaded 

the Sig Sauer P229 semiautomatic he purchased six days prior. He then walked to the 

FRC’s headquarters, arriving at 10.46am. He gained access to the building claiming to 

be there for an interview for an internship. Upon entering the building, an unarmed 

security guard seated at reception asked to see Corkins’ identification. Corkins pulled 

a handgun from his backpack and pointed it at the security guard. The security guard 

rushed at Corkins and in the ensuing struggle Corkins shot three times, one of which 

hit the guard’s arm. Despite this injury, the guard managed to overpower and subdue 

Corkins until the Metropolitan Police Department arrived. The police searched 

Corkins and found two fully loaded magazine clips, 50 rounds of 9mm ammunition, 

15 Chik-fil-A chicken sandwiches and a handwritten list including the names of four 

organizations including the FRC that Corkins previously researched online. 

Post-Event Activity and Strategic Analysis 

There is no publicly available information with regards to this stage. 

Abdulhakim Mujahid Muhammad 

At 10.19am on June 1st 2009, Abdulhakim Mujahid Muhammad (formerly Carlos 

Bledsoe) conducted a drive-by shooting on soldiers outside of a U.S. military 

recruitment office in Little Rock, Arkansas, killing one and injuring one. 

Decision and Search Activity Stage 

Muhammad acknowledges membership in a gang prior to his conversion to Islam in 

2004 (http://www.commercialappeal.com/jihad/competency-evaluation/). He left 

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
68

school at 12th grade and experienced a number of suspensions previously because of 

fighting. Gartenstein-Ross’ (2014) in-depth case study of Muhammad utilized police 

and court records that illustrated how Muhammad had previously come into contact 

with authorities in relation to (1) a 2002 fight with another former gang member (2) a 

2002 altercation that involved a knife being pulled (3) a 2003 car crash to which 

Muhammad reacted by first running to the other driver’s vehicle and “hitting the rear 

passenger window with chrome-plated brass knuckles. Muhammad yelled, ‘Bitch I’m 

gonna kill you, get out, I’m going to kill you when I get your address” (GartensteinRoss, 2014:113) (4) a 2004 incident in which police found Muhammad in a car 

alongside a SKS assault rifle and a single-shot shotgun that Muhammad claimed he 

was selling to an individual who successfully fled from police. He was also found in 

possession of a bag of marijuana. All of these events occurred before he turned 20. He 

converted to Islam soon after being charged and receiving a 14-year suspended 

sentence for the unlawful weapons and drug possession offence.

In his justification statement, Muhammad states: “There’s an all out war against Islam 

and Muslims in Afghanistan, Pakistan, Waziristan, Chechnya, Somalia, Palestine, 

Phillipines, Yemen etc. And Muslims have to fight back...We believe in an eye for 

eye not turn the other cheek. Now it’s all out war on American and I’m on the other 

side. The side of the Muslims – Yes! The side of Al-Qaeda – Yes! Taliban- Yes! AlShabaab – Yes! We are all brothers under the same banner. Fighting for the same 

cause which is to rid the Islamic world of Infidel and Apostate Hypocritic [sic] 

regimes and Crusader Invaders and re-establish the Caliphate, the Islamic Empire and 

Islamic Law as was ended officially in 1924 by the fall of the Ottomans” (cited in 

Gartenstein-Ross, 2014:118). Here, Muhammad not only aligns with and portrays 

himself as being the same as Al-Qaeda, the Taliban and Al-Shabaab, he also places 

himself in a long historical narrative of resistance that has been ongoing since 1924. 

In September 2007, he left the U.S. for Yemen ostensibly to learn Arabic. During this 

time, he apparently radicalized further. He desired entry into Somalia to obtain 

militant training. Before he could leave, Yemeni authorities arrested him in October 

2008. He returned to the U.S and to his hometown of Little Rock in January 2009. 

Preparation Stage 

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
69

Upon his return to the U.S., Muhammad began planning an attack. He researched 

potential targets online including military facilities, Jewish centers, a post office, a 

Baptist church and a childcare center. These targets were geographically spread and 

included Little Rock, Memphis, Nashville, Florence, Kentucky, Philadelphia, 

Baltimore and Washington D.C 

He claims the eventual attack “wasn’t part of Plan A. Plan A was aborted because of 

failed attacks in Tennessee and Kentucky”. In Nashville Tennessee, his attempt to 

firebomb a Rabbi’s house failed when the Molotov Cocktail bounced harmlessly off 

the window rather than smashing through it. In Florence, Kentucky a drive-by 

shooting at an Army recruitment center was called off when he realized it was closed 

as he arrived. 

So, the eventual attack at “the Crusader Center in Little Rock was Plan B. And 

compared to what I had planned originally, it was like a grain of sand. One crusader 

dead, one wounded, 15 terrorized, big deal. Nidal Malik is the real Islamic Warrior, 

and my plan A was on that scale. It included Little Rock, Memphis, Nashville, 

Florence KY, Philadelphia, Baltimore, and was supposed to end in DC.” He also 

lamented his failure to obtain bomb-making training in Yemen or Somalia. “I wanted 

training in explosives, on how to make bombs and in particular, car bombs, and had I 

got this training my story would have ended a lot differently than it’s going to end 

now. My drive-by would have been a drive-in, with none escaping the aftermath”10

.

He bought a series of firearms second-hand. Finally, he bought a .22 rifle “over the 

counter at Wal-Mart to test if I’d get caught or questioned”. It was a “test to see if I 

was under surveillance”. Once the new gun was purchased, he thought to himself “It’s 

on...Meaning, I’m not under surveillance. The FBI had not put a hold or checked” 

(http://www.commercialappeal.com/jihad/competency-evaluation/). 

 

10 Scanned copies of these Muhammad’s correspondence with Katrina Goetz can be 

found at http://www.commercialappeal.com/jihad/ 

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
70

The night before his attack, he watched a number of jihadist videos online. 

Muhammad attributed one particular video as the sole reason for his shooting. “I 

started seeing more pictures of just women being raped you know, gang raped and 

you know it’s one woman named Fatima, she’s in a prison so she got raped more than 

nine times on one day and she was wanting to kill herself and you know it was just –

it was a point of insanity, I ... I think is what happened and I just like blacked out you 

know. And...and I just kind of went insane all of a sudden”. This is a highly unlikely 

scenario given the extensive planning it took to become as equipped with firearms as 

Muhammad became. 

Event Execution Stage 

On the morning of June 1st, Muhammad drove to the recruitment center at Little Rock 

and fired a semi-automatic rifle at two individuals having a cigarette outside the 

center. He shot both and continued firing at the center, hoping to hit at least some of 

the 15 individuals located inside. Muhammad fled the scene in his vehicle. Police 

apprehended him eight miles from the attack location. He was in possession of two 

rifles (one with a scope and laser sight), two handguns (one semi-automatic), 562 

rounds of ammunition, homemade sound suppressors, and binoculars. Police also 

found Molotov Cocktails in his home. 

Post-Event Activity and Strategic Analysis 

There is no publicly available information with regards to this stage. However, 

following his arrest, Muhammad’s violence continued in jail. On one occasion he 

stabbed a fellow inmate, on another occasion the victim was a prison guard. He used a 

shank both times. Muhammad has also been associated with a number of threats 

against prison staff and repeatedly vandalizing his cell. 

Eric Rudolph 

On July 26th 1996, Eric Rudolph committed a bombing attack at the 1996 Atlanta 

Olympics. The bombing killed one civilian and injured a 111. 

Decision and Search Activity Stage 

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
71

Over the course of 18 months, Rudolph bombed two abortion clinics, the Atlanta 

Olympics and a lesbian bar. He carried out all of the planning, preparation and actions 

alone. Yet, in his numerous writings throughout the bombing campaign, during his 

sentencing and while in prison, Rudolph depicts himself as part of a wider movement 

of anti-abortion activists. As noted by Seegmiller (2007), between 1973 (when 

abortion was legalized in the U.S.) and 2007, over 200 abortion clinics were bombed 

or set on fire and over 4000 acts of violence were carried out or threatened against 

abortion providers. Rudolph sees himself as just one component of what is a wider 

movement of committed action. He “frames his activism and identity as connected to 

an amorphous milieu of violent, radical anti-abortion activists who largely draw upon 

religious authority, biblical language, and apocalyptic narratives to frame and justify 

their activities” (Seegmiller, 2007: 521). Indeed, Rudolph’s writings are hosted on the 

Army of God website including his 240 page autobiography which suggests they view 

him as one of their own also. The autobiography states that Rudolph’s goal was to 

overthrow an illegitimate government but he acknowledges “Naturally, I couldn’t do 

it alone. I had no delusions on that score. I had to somehow encourage others to 

help...The hope was that my actions would push other pro-lifers and Patriots to 

bridge the gap between their rhetoric and their actions” (Rudolph, 2013:5-6). Rudolph 

had also grown quite skeptical of how effective the pro-life movement had become 

while it remained on a non-violent course. “The masters of the media have censored 

the pro-life movement out of the mainstream society. The protestors...might as well 

be on the moon as far as most Americans are concerned. I was planning my own 

protest for the anniversary of Roe v. Wade. Unlike other protests, mine wouldn’t be 

ignored. I planned to blow Northside Family Planning off the map” (Rudolph, 

2013:27). 

During the Spring of 1995, Rudolph decided to turn to violence. He decided to “carry 

out a series of high profile attacks against symbols of the regime: abortion mills, 

Sodomite organizations, left-wing interest groups, and agents of the Washington 

government...These attacks were not part of some personal vendetta against 

abortionists, homosexuals, or government agents; they were acts of war aimed at 

damaging, undermining and ultimately, overthrowing the liberal establishment in 

America. When I heard they were bringing the Summer Olympics to Atlanta, I 

thought it would make the perfect target” (Rudolph, 2013:6).

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
72

On the Atlanta Olympics bombing, Rudolph’s justification states: 

“In the summer of 1996, the world converged upon Atlanta for the Olympic 

Games. Under the protection and auspices of the regime in Washington 

millions of people came to celebrate the ideals of global socialism/ 

Multinational corporations spent billions of dollars, and Washington organized 

an army of security to protect these best of all games. Even though the 

conception and purpose of the so-called Olympic movement is to promote the 

values of global socialism, as perfectly expressed in the song Imagine by John 

Lennon, which was the theme of the 1996 Games even though the purpose of 

the Olympics is to promote these ideals, the purpose of the attack on July 27 

was to confound, anger and embarrass the Washington government in the eyes 

of the world for its abominable sanctioning of abortion on demand. The plan 

was to force the cancellation of the Games, or at least create a state of 

insecurity to empty the streets around the venues and thereby eat into the vast 

amounts of money invested.”

The decision to act alone was simple. He outlined that he had “been around long 

enough to know the pitfalls of collaboration” (Rudolph, 2013:6). He later lamented 

the lack of help during his fourth bombing (the one that led to his capture): “Oh, how 

easy it would be if I had a partner...Though working alone had its advantages, 

namely, there was nobody to rat me out, it also made a quick execution and getaway 

more difficult” (Rudolph, 2013:42). It also appears he was inspired by other lone 

actors. In his autobiography, Rudolph begins the Olympics bombing chapter with two 

paragraphs telling the story of Paul Hill. For Rudolph, Hill “seemed like a perfect 

anomaly, a genuine American hero in an age of cowardice. I’d read about such people 

in history books, but I didn’t think they existed anymore. I knew then that the era of 

hot air was over. People were finally bridging the gap between their rhetoric and their 

actions. I knew then it was time for me to act as well” (Rudolph, 2013:3).

Preparation Stage 

In June 1996, Rudolph left his hometown and rented a trailer forty miles west. 

Rudolph initially wanted to bomb Atlanta’s power grid during the Olympics rather 

than place a bomb at the Olympics itself. He dropped this plan because “making 

enough charges to disable Atlanta’s power grid would take too much time and money. 

I had neither. The Olympics was fast approaching, and I needed to come up with a 

new plan” (Rudolph, 2013:7). Instead he turned to smaller pipe bombs. Rudolph 

“drove 100 miles to Gadsden, Alabama, where I bought pipes, alarm clocks, batteries, 

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
73

and circuit wire. Then I drove a little more, hoping to make my activities hard to 

track” (Rudolph, 2013:7). In total, he spent six weeks manufacturing and testing his 

IEDs. During this time Rudolph feared that his landlady, who searched his trailer on a 

number of occasions, could have rumbled his preparations. The opportunity to test 

these IEDs in the “remote hollows along the North Carolina-Tennessess border” 

undoubtedly helped Rudolph’s plot develop from a technical standpoint (Rudolph, 

2013:7). 

A couple weeks prior to the eventual bombing, Rudolph surveilled security at the 

Olympics. For this task, he wore a light disguise. He noticed “there were no metal 

detectors, and bags were searched selectively. After sundown the crowds grew 

enormous. Upwards of a hundred thousand people packed into Five Points. Security 

at the park became overwhelmed. They stopped searching bags altogether, and the 

entrances flew wide open. I knew then that I could smuggle in a bomb” (Rudolph. 

2013:10). 

Rudolph pushed back the date of his initial IED attack on the Atlanta Olympics when 

his truck was broken into and a window was smashed in the process. Rudolph feared 

police pulling him over for the broken window so he fixed it before he could use the 

truck to transport his pipe bombs to the target site (Rudolph, 2013:11). 

Rudolph also slept rough the nights before the bombing hoping to avoid the CCTVs 

installed at hotels. 

Rudolph’s last task before setting off to bomb the Atlanta Olympics was to bury an 

emergency cache in the woods that contained enough food, oil and camping 

equipment to allow him to survive for a year. 

Event Execution Stage 

On the night of the bombing itself, a third-party took a picture of a water fountain at 

the Olympic Park. Rudolph was convinced he also was in the picture and in his 

autobiography admits that this was enough to engender “several tense moments of 

indecision” and the “strong urge to flee” without priming and detonating the IED 

(Rudolph, 2013:13-14). Rudolph claims the plan was to disrupt the Olympics, not for 

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
74

the bomb to detonate. After priming the device, he sought to leave a warning with 

police from a pay phone. Rudolph notes: “Quickly, I stuffed each nostril with wet 

toilet tissue and slipped on my pair of gloves and pulled a little plastic funnel from my 

pocket. The tissue and funnel should help distort my voice. ‘Atlanta – nine – one –

one’ said the woman operator. ‘Do you understand me?’ I asked. ‘Yah’. ‘We defy 

your...’ suddenly the line went dead”. Rudolph’s attempt to provide a justification 

alongside the warning failed. Rudolph then left that scene and found another set of 

payphones close by “but the street was packed with people. Groups of tourists 

shuffled past me. I waited. Agonizing minutes were wasted. A break in the crowd 

developed. I faced the other way and found a phone. ‘Make it quick; just a flat 

warning; no statement’ I told myself” (Rudolph, 2013:14). Without leaving the 

justificatory message, Rudolph acknowledges that the bombing “sent the wrong 

message. Aimed at Washington and the corporate sponsors, the bombing came off as 

an indiscriminate attack on innocent civilians. I would see to it that never happened 

again. From now on I’d choose specific targets” (Rudolph, 2013:21). 

Post-Event Activity and Strategic Analysis 

In his sentencing remarks for the Olympics bombing and in his autobiography, 

Rudolph refers to the victims as “innocent civilians” and that he felt “much remorse” 

because of the “fatal decision”, “horrible mistake” and “dangerous tactic” of planting 

the bomb in a crowded area, calling in an advanced bomb warning, and hoping that 

the area would be cleared of civilians. 

This ‘mistake’ did not dissuade Rudolph from violent action however. In the months 

preceding the Atlanta bombing, Rudolph also bombed two abortion clinics and a 

lesbian bar (which reflects with his theorizing that only specific targets should be hit 

in order for the violence not to be message-less like the Olympics bombing). The 

second abortion clinic bombing killed a security guard and critically injured a nurse. 

In his sentencing remarks for the abortion clinic fatalities, Rudolph commented “I did 

not target them for who they were – but for what they did. What they did was 

participate in the murder and dismemberment of upwards of 50 children a week”. In 

Rudolph’s eyes, these were legitimate targets.

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
75

Rudolph gave up on producing enough explosives for the main charge of his later IED 

attacks, stating that the effort was “not worth the cost in time, money and brain cells” 

(Rudolph, 2013:22). Instead, he turned to stealing commercial explosives from 

quarries and an explosives manufacturer. 

Scripting Lone actor Terrorist Events 

Figure 5.1 below outlines a diagram of the lone actor terrorist event script. It 

highlights the complexity of the first two stages, particularly the preparation phase. 

Figure 5.1 Lone Actor Attack Script

Solo Terrorists 

Faisal Shahzad 

On the evening of May 1, 2010, Faisal Shahzad, a 30 year-old U.S. citizen, drove an

SUV rigged with an improvised explosive device (IED) into a still-crowded Times 

Square in New York City. He parked the vehicle, activated the bomb, and 

walked away. Police were alerted, the IED was safely dismantled, and there were no 

casualties. 

Decision and Search Activity Stage

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
76

Born in Pakistan in 1979; his father is a retired Pakistani Air Force official who 

provided an upper middle-class lifestyle for his family, with chauffeurs and servants. 

In January 1999, Shahzad was granted a student visa and came to the U.S., enrolling 

in college in Washington, D.C., and later transferring to the University of 

Bridgeport in Connecticut, from which he graduated with a Bachelor’s degree in

computer science. In April, 2002, Shahzad received another three-year visa, and he 

started graduate studies at the University of Bridgeport. Here Shahzad worked 

toward an MBA alongside working in accounting at the global cosmetics firm

Elizabeth Arden. Upon graduating Shahzad found work as an analyst at the financial 

marketing firm Affinion Group. During this time, Shahzad bought and sold a 

condominium in Norwalk, Connecticut and then bought a house in Shelton, 

Connecticut. In 2004, Shahzad married Huma Mian, a 23 year-old accountant from 

Denver, Colorado. 

By 2006, friends noticed that Shahzad became more religious and distanced himself 

from what he considered the liberal ‘elite’ world of his father. He stopped drinking 

alcohol, prayed five times a day, and began frequenting Mosques in Stamford, 

Norwalk, and Bridgeport. In February 2006, Shahzad’s ideological fervor was more 

open noticeable. In an email to a group of friends, Shahzad’s distress regarding the 

wars in Iraq and Afghanistan, and the publication in Denmark of cartoons 

ridiculing the Prophet Mohammed was clearly evident: 

"It is with no doubt that we today Muslim, followers of Islam are attacked and 

occupied by foreign infidel forces. The crusade has already started against Islam 

and Muslims with cartoons of our beloved Prophet PBUH as War drums... 

Everyone knows how the Muslim country bows down to pressure from west 

[sic]. Everyone knows the kind of humiliation we are faced with around the 

globe." 

In other e-mail messages, Shahzad argued that the West is at war with Islam, and 

that Muslims have strayed from their religious duty to fight back. The Internet 

messages of Anwar al-Awlaki reportedly inspired his devout, radical behaviors.

During a visit to Pakistan in 2008, Shahzad asked his father for permission to

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
77

fight in Afghanistan, a request his father denied.

In an April 2009 ceremony at the federal courthouse in Bridgeport, Connecticut, 

Shahzad became a U.S. citizen. It was around this time that Shahzad appeared to be 

struggling financially, complaining to a friend that he found it stressful to keep 

up with mortgage payments. Others noticed strains in his marriage. He pressured his 

wife to wear a hijab, and insisted that she should not work, despite their financial 

issues. In February 2009, Shahzad obtained a $65,000 equity loan. In June, Shahzad

stopped paying his mortgage and other bills, and on 2nd June, 2009, he and his 

family left the U.S. 

 

Preparation Stage 

After departing the U.S. for his hometown in Pakistan, Shahzad abruptly left his 

family on 9th December, 2009, and travelled to Taliban training camps in North 

Waziristan where he received bomb-making training from trainers affiliated with 

Tehrik-e-Taliban. It was during this time the plot was devised. Shahzad also met 

with a member of Lashkar-e-Taiba, the group responsible for the attacks on the 

Indian city of Mumbai in 2008. Shahzad requested money from Tehrik-e-Taliban, and 

received $4,000. Shahzad later claimed to have met with Taliban leader Hakimullan 

Mehsud and that the attack on Times Square was retribution for Mehsud's death in a 

drone strike. 

On February 2nd 2010, Shahzad returned to the U.S. on a one-way ticket from 

Pakistan. Due to the recent "underwear bomber" scare in December 2009, he was 

subjected to extra screening by U.S. Customs. During this conversation, Shahzad 

stated to officials that he had been in Pakistan for five months, and he indicated that 

he intended to stay at a hotel in Connecticut whilst he arranged for more permanent 

work and living arrangements. Shahzad provided a telephone number (which 

belonged to a pre-paid mobile that was activated on 16th April 2010). Shahzad then 

spent three weeks looking for more permanent accommodation, where he could have 

privacy to carry out the preparation. 

Shahzad received two monetary donations from a member of Tehrik-e-Taliban during 

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
78

the preparation stage. The first occurred on 25th February, 2010. Shahzad received 

$5,000 in cash in Massachusetts. The second occurred on 10th April, 2010, in 

Ronkonkoma, New York, and totaled $7,000. Shahzad admitted that these donations 

were for purchasing the components for the attack. 

On 15th March, 2010, Shahzad purchased a semi-automatic 9 millimeter Kel-Tec rifle in 

Connecticut. 

In mid-April, Shahzad used the pre-paid mobile to approach an individual selling a 

1993 Nissan Pathfinder. During the initial conversation Shahzad arranged to meet 

with the seller on 24th April in a Supermarket car park in Connecticut. The pre-paid 

mobile was contacted four times on the morning on 24th April, 2010, by a number in 

Pakistan. These phone calls highlight the extent to which Shahzad acted under 

direction of a larger group. It was after these calls were made that Shahzad rang the 

seller of the Pathfinder twice. Shahzad met with the seller, and purchased the vehicle 

for $1,300 using cash on the afternoon of 24th April 2010. Shahzad changed the 

registration plates, and tinted the windows following the transaction. On 25th April 

2010, Shahzad again used the mobile to contact a fireworks store on Pennsylvania. 

These calls were all made prior to 28th April 2010, when the phone was cut off. 

During April, 2010, Shahzad also purchased the various constituent parts of the IED, 

and used a garage at his residence to store them. Shahzad also reportedly carried out a 

dry run in the Pathfinder on 28th April, 2010, driving around to seek out the most 

appropriate place for the event. 

Event Execution Stage 

The IED consisted of three full propane tanks, two five-gallon gasoline canisters, 

several plastic bags containing fertilizer, 152 M-88 fireworks, and two alarm clocks 

connected to wiring. 

Shahzad drove from Connecticut to New York on 1st May 2010. At 18:30 UTC, he 

attempted to detonate the IED in the Nissan Pathfinder vehicle at 45th Street and 

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

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79

Seventh Avenue in Manhattan. He initiated the device, left the engine on, and walked 

to Grand Central Station, catching a train to Connecticut. 

Post Event Activity and Strategic Analysis 

A member of the public informed a mounted police officer of the presence of the 

unoccupied Pathfinder. When the officer approached the car, he observed smoke 

emanating from it, and he summoned assistance. The entire area was evacuated, and 

the NYPD bomb squad and fire department responded to the scene. When law 

enforcement officers searched the Pathfinder, a number of keys were recovered, 

including the key to an Isuzu Rodeo vehicle, and his Connecticut residence. 

A video was posted online on 2nd May 2010. This video showed Shahzad explaining 

his reasoning behind his decision to act. It was narrated by Qari Hussain Mehsud, a 

chief bomb maker, and claimed that the Taliban in Pakistan was responsible for the 

attack. Two subsequent follow up videos were also posted on 3rd May 2010, showing 

meetings between Shahzad and Hakimullah Mehsud, and threatened further attacks 

against the U.S. and NATO allies. 

Shahzad was arrested on May 3rd 2010 at 23:45 UTC at John F. Kennedy 

International Airport, as he attempted to leave the U.S. on a flight to Dubai. 

Subsequent to his arrest, Shahzad admitted to officers that he had attempted to 

detonate the device in Times Square, he had received training in Waziristan and 

Pakistan, and that he had driven a car to the airport on 3rd May, 2010, and that there 

was a gun in this car. Officer’s recovered this car on 4th May, 2010, and found the 

Kel-Tec rifle. 

During detention, Shahzad repeatedly waived his Miranda rights. He provided agents 

with details regarding ongoing movements of subjects of investigation, which led to 

arrests. He also admitted that had he not been arrested, he would have detonated 

another bomb in New York City two weeks later. Shahzad was indicted in federal 

court; an excerpt of his underlying intentions is given below: 

THE COURT: “Last year. Didn't you swear allegiance to this country when you 

became an American citizen?”

SHAHZAD: “I did swear, but I did not mean it.”

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80

THE COURT: “I see. You took a false oath?”

SHAHZAD: “Yes.”

THE COURT: “Very well. Is there anything else you want to tell me?”

SHAHZAD: “Sure. I am ashamed that I belong to a slave country like Pakistan, 

who has accepted the slavery of the West from the day it was born. Bush had 

made already clear when he started the war on us, on Muslims, he said: You are 

either with us or against us. And so it's very clear for us Muslims, either we are 

with the mujahideen or we are with crusading losing Christians. There is no in 

between. Blessed be the immigrants and the leader Sheikh Osama Bin Laden, 

who will be known as no less than Saladin of the 21 century crusade and blessed 

be those who give him asylum.”

On 21st June, 2010, Shahzad pled guilty to all charges, and was sentenced to life in

prison. He repeatedly expressed his total lack of remorse, and his desire to repeat the 

crime, if he were given the opportunity. 

At his sentencing hearing on 5th October, 2010, Shahzad requested to make a speech 

prior to any decision. This was granted: 

“In the name of Allah, the most gracious, the most merciful, this is but one life. If 

I am given a thousand lives, I will sacrifice them all for the sake of Allah fighting 

this cause, defending our lands, making the word of Allah supreme over any 

religion or system. We Muslims don't abide by human-made laws, because they 

are always corrupt... The sentence the judge will not mean anything to me, for how 

can I be judged when the Court does not understand the suffering of my people. 

They don't understand my side of the story, where the Muslim life of is no value. 

Therefore, the only true judgment will be on the day of resurrection when Allah 

will judge between me and you as to who is fighting for the just cause. So decree 

whatever you desire to decree, for you can only decree regarding the life of this 

world. The crusading U.S. and NATO forces who have occupied the Muslim lands 

under the pretext of democracy and freedom for the last nine years and are saying 

with their mouths that they are fighting terrorism, I say to them, we don't accept 

your democracy nor your freedom, because we already have Sharia law and 

freedom. Furthermore, brace yourselves, because the war with Muslims has just 

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
81

begun. Consider me only a first droplet of the flood that will follow me... So let's 

see how you can defeat your Creator, which you can never do. Therefore, the defeat 

of U.S. is imminent and will happen in the near future, inshallah, which will only 

give rise to much awaited Muslim caliphate, which is the only true universal world 

order... We are only Muslims trying to defend our religion, people, honor, and 

land. But if you call us terrorists for doing that, then we are proud terrorists, and 

we will keep on terrorizing until you leave our land and people at peace. But if you 

don't, then I remind you that we have watches and we have time. We will defeat 

you with time.”

Umar Farouk Abdulmutallab 

On 25th December 2009, Abdulmutallab boarded Northwest Airlines Flight 253 from 

Amsterdam to Detroit. He ignited an incendiary device shortly before arrival in 

Detroit in an attempt to destroy the plane, and 289 individuals on board. There were 

no fatalities or serious injuries. 

Decision and Search Activity Stage 

Abdulmutallab reportedly became very pious in his religion during his teenage years 

in Nigeria. He spent his free time reading the Quran, and earned the nickname 

“Alfa ”. Over 300 Internet postings under the handle “farouk1986” were identified. 

Abdulmutallab spoke of love, his future ambitions, and his inner struggle between 

liberalism and extremist as a devout Muslim. In January 2005, Abdulmutallab 

confessed: 

“I am in a situation where I do not have a friend. I have no one to speak too, no one 

to consult, no one to support me and I feel depressed and lonely. I do not know 

what to do and then I think this loneliness leads me to other problems...I get lonely 

sometimes because I have never found a true Muslim friend”. 

Abdulmutallab’s postings display his gradual ideological changes towards more 

devout Islamic opinions and practices, and display his views of violence and 

extremism, without specific mention of his own choice to follow such behaviors. 

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
82

However, when Abdulmutallab enrolled in mechanical engineering at University 

College London in September 2005, his religious beliefs began attracting attention. 

Abdulmutallab became head of the campus branch of the Islamic Society in 2006, 

inviting controversial speakers, and former Guantanamo Bay inmates to attend 

functions. He regularly attended prayers at London Mosques monitored by the British 

security services. He was seen ‘reaching out’ to known extremists, and was noted as 

being ‘on the periphery’ of various investigations. He was not, however, considered a 

threat by British counterintelligence. 

In June 2008 Abdulmutallab graduated and was granted a multiple entry tourist visa 

to the United States (U.S.). In January 2009, Abdulmutallab enrolled at the University 

of Wollongong, Dubai to study a business course. In August 2009, Abdulmutallab 

dropped out and travelled to Yemen, studying at the Sana’s Institute for Arabic 

Language. At this time Abdulmutallab attempted to return to England, but his student 

visa request was refused. Abdulmutallab later explained that he travelled to Yemen to 

meet radical Imam Anwar al-Awlaki, after studying his preachings. Whilst attending a 

Mosque in Yemen, Abdulmutallab was introduced to ‘Abu-Tarak’, who was allegedly 

a member of Al-Qaeda, and during daily discussions, they discussed various ways to 

attack the U.S. In October 2009, Abdulmutallab travelled to the Shabwa Province, 

and attended an Al-Qaeda training camp, purportedly under the direction of alAwlaki. In November 2009, Abdulmutallab agreed to become involved in an aerial 

martyrdom attack against the U.S. It was also during this time that Abdulmutallab 

contacted his parents, and hinted at his involvement in a movement. His father 

contacted CIA officials at the United States embassy in Nigeria, expressing concerns 

for his son. 

Preparation Stage 

Abdulmutallab claimed to have met the bomb maker, a Saudi Arabian individual, 

whilst in Yemen. The device, consisting of Pentaerythritol Tetranitrate (PEIN) and 

Triacetone Triperoxide (TATP), weighed approximately 200g. The device had no 

metal parts, and therefore would not alert airport security. Detonation was to be 

achieved by injecting liquid acid into the PEIN and TATP at a time of choosing. The 

device was designed to be part of Abdulmutallab’s underwear. Prior to leaving 

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
83

Yemen, Abdulmutallab recorded a video. The video showed Abdulmutallab at a 

desert training camp shooting at targets including a Jewish star, the British 

Union Jack flag, and the initials "UN". Abdulmutallab’s statement was only a portion 

of the video: 

"Oh, ye who believe, take not the Jews and the Christians for your allies and 

protectors. They are but allies and protectors to each other and he amongst you that 

turns to them is of them. Verily, Allah guides not a wrongdoing people... My 

Muslim brothers in the Arabian Peninsula, you have to answer the call of jihad 

because the enemy is in your land along with their Jewish and Christian armies. 

Allah, the most high... unless you go forth... He [Allah] will punish you with a 

grievous penalty and put others in your place. But him... you would not harm in 

the least." 

Abdulmutallab was instructed to destroy a U.S. aircraft over U.S. territory, however 

he was given complete control over which airliner, and which flight. This highlights 

that he networked with others in an organization, yet acted alone. In December 2009, 

Abdulmutallab left Yemen, and flew then to Ghana, then Nigeria, then Amsterdam. 

Abdulmutallab wore the device in his underwear continuously from leaving Yemen. 

In the Netherlands, Abdulmutallab boarded Northwest Airlines flight 253 to Detroit 

on 25th December 2009. Abdulmutallab had attempted to book onto flights to 

Houston, Chicago, and California, and told travel agencies numerous false scenarios 

in order to secure a flight. Whilst passing through U.S. preclearance Abdulmutallab 

provided false information and details to customs officers. When Abdulmutallab 

boarded the plane, he engaged in rituals, he fasted and spent an extended period of 

time in the airplane toilet, purifying himself. 

Event Execution Stage 

Abdulmutallab returned to his seat, explained to his neighboring passenger that he felt 

unwell, and covered himself with a blanket. At 11:44 EDT, Abdulmutallab pressed a 

button to detonate the device. Several passengers reported hearing a loud pop, which 

reportedly sounded like a firecracker. The TATP in the device did explode, but the 

PETN failed to ignite, the result of which was a small fire, which engulfed 

Abdulmutallab’s groin area, and spread to the carpet, walls, and seat. Passengers 

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
84

restrained Abdulmutallab, and removed him from seat 19A (a window seat on the 

wing), walked him down the plane, and placed him in seat 1G, where he could be 

monitored. Abdulmutallab’s clothing and shoes were removed, and he was given a 

blanket to cover himself with. The captain was informed of a fire, and brought Flight 

253 into a steep descent, and landed the plane at 11:49 EDT. 

Post Event Activity and Strategic Analysis 

Whilst the plane was being brought into Detroit airport, Abdulmutallab spoke to a 

passenger and a steward who sat with him to ensure he would carry out no further 

disruption. Abdulmutallab explained that he had triggered an explosive device on his 

person. Abdulmutallab proceeds to tell each individual he came into contact with 

what his actions were. The conversation with the U.S. customs officer is detailed 

below: 

Officer Steigerwald: "What is going on? What were your intentions on the 

flight?" 

Abdulmutallab: "To bring down the airplane." 

Officer Steigerwald: "Who are you involved with?" 

Abdulmutallab: "Al-Qaeda." 

Officer Steigerwald: "Where did you get the device?" 

Abdulmutallab: "Yemen, in the Middle East." 

Officer Steigerwald: "Who are you involved with?" 

Abdulmutallab: "I'm with al-Qaeda." 

Officer Steigerwald: "What kind of device was it?" 

Abdulmutallab: "A bomb." 

Officer Steigerwald: "What were your intentions?" 

Abdulmutallab: “To bring the plane down over U.S. soil." 

Officer Steigerwald: "Where did you have the device?" 

Abdulmutallab: "In my underwear." 

Abdulmutallab is then transported to the University of Michigan Hospital, during 

transportation he has a conversation with a paramedic: 

Jessica Worsley: "Where's that powder from?" 

Abdulmutallab: "There was a syringe and they told me to push the syringe in the 

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
85

stitching of my clothing" 

Jessica Worsley: "Who is they?"... "Were you trying to commit suicide or harm 

yourself?" 

Abdulmutallab: "Yes" 

Abdulmutallab arrives at the Hospital at 12:25 EDT. A conversation Abdulmutallab 

had with a nurse between 14:30 and 15:00 EDT was also recorded: 

Julia Longenecker: “Have you ever thought about harming yourself or others?”

Abdulmutallab: “No”

Julia Longenecker: “Well, what about what happened on the plane today? Didn’t 

you try to harm yourself or others?”

Abdulmutallab: “That was martyrdom.” 

At the hospital, Abdulmutallab has a converses with Dr. James Pribble. He describes 

how the bomb worked, and that he injected a syringe into powder, and it triggered the 

explosion. Abdulmutallab also requested that Christmas music playing throughout the 

hospital to be turned off.

At 15:35 EDT, when Abdulmutallab had been sufficiently treated at the Hospital, two 

FBI agents, Special Agent Peissig, and Timothy Waters interviewed him. The 

interview lasted between 45 and 50 minutes, during which Abdulmutallab explained 

the entire plot. Abdulmutallab told the agents that he went to Yemen in order to 

become involved in the jihad against the U.S. He explained that he tracked down and 

found Al-Qaeda, he explained his introduction to Abu-Tarak, and their daily 

conversations regarding plans to attack the U.S. Abdulmutallab went on to explain 

how the suggestion to target a U.S. plane was put into action. He spoke at length of 

meeting with the Saudi Arabian bomb maker, and the engineering behind the device. 

Abdulmutallab then detailed his travel from Yemen to the U.S. 

The martyrdom video – titled “America and the Final Trap”- that Abdulmutallab 

recorded prior to leaving Yemen was released following the attack. In the video, AlQaeda claimed responsibility for the attack, explaining how the bomb defeated 

Western airport security, and why Abdulmutallab turned to jihad. 

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
86

During forensic testing of what remained of the device, officials found fingerprints on 

the underside of the tape that held the bomb together. The fingerprints were not 

Abdulmutallab’s, and it was concluded they were left by another individual who 

assembled the device. This corroborates Abdulmutallab’s statements regarding the 

Saudi Arabian bomb maker. Forensic experts also found an encryption code for 

communication with Al Qaeda written on a slip of paper, in Abdulmutallab’s shoe. It 

was purported that Abdulmutallab used this encryption code to communicate with 

someone just prior to boarding the plane. 

Abdulmutallab’s initial court appearance was 26th December 2009, he agreed to be 

represented by the Federal Public Defender’s Office. However, on 13th September 

2010, Abdulmutallab informed the pre-trial hearing that he wished to represent 

himself, as he believed representation appointed to him by the American district court 

would not be in his best interests. The conversation went as follows: 

The Court: “Mr Abdulmutallab, I must advise you that in my opinion you would 

be far better defended by a trained lawyer than you can be by yourself. I think 

it is unwise of you to try to represent yourself. You’re not familiar with the law, 

you are not familiar with court procedure, you’re not familiar with the rules of 

evidence, and I would strongly urge you not to try to represent yourself. Now, 

in light of the penalty that you might suffer if you are found guilty, and in light 

of all the difficulties of representing yourself, is it still your desire to go forward 

and represent yourself without giving another try to having an attorney represent 

you, just even over the next month or two, to see if perhaps we can appoint an 

attorney who would have what you believe to be your best interests in mind?”

Abdulmutallab: “Yeah, I don’t want that, no.”

The Court: “You don’t want another attorney?”

Abdulmutallab: “No.”

The Court: “Is your decision entirely voluntary on your part?”

Abdulmutallab: “Yeah.”

The Court: “All right. I find that the defendant has knowingly and voluntarily 

waived his right to counsel, and I will permit him to represent himself. However, 

I am going to appoint standby counsel, which I would always do in the case of 

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
87

trial, but I believe this case demands that we have standby counsel available for 

you to consult with for any questions that you might have as you prepare to 

represent yourself at the trial in this matter.”

On 5th August 2011, Abdulmutallab’s standby counsel filed a motion to suppress the 

statements Abdulmutallab made at the Hospital, and a motion for a competency 

hearing under seal. Abdulmutallab claimed that the witness statements from the 

Hospital should be suppressed, as he was not given a Miranda warning prior to 

making the statements, and he was under the influence of the pain-relief medication 

Fentanyl at this time. This was rejected. 

On 12th October 2011, Abdulmutallab pled guilty to all eight counts against him, and 

released this statement, which highlights the degree of the command and control links 

with others in Al Qaeda: 

“In the name of Allah, the most merciful, if I were to say I the father did not do 

it, but my son did it and he conspired with the holy spirit to do it, or if I said I did 

it but the American people are guilty of the sin, and Obama should pay for the 

crime, the Court wouldn’t accept that from me or anyone else. In late 2009 in 

fulfillment of a religious obligation, I decided to participate in jihad against the 

United States. The Koran obliges every able Muslim to participate in jihad and 

fight in the way of Allah, those who fight you, and kill them wherever you find 

them, some parts of the Koran say, an eye for an eye, a tooth for a tooth. I had an 

agreement with at least one person to attack the United States in retaliation for 

U.S. support of Israel and in retaliation of the killing of innocent and civilian 

Muslim populations in Palestine, especially in the blockade of Gaza, and in 

retaliation for the killing of innocent and civilian Muslim populations in Yemen, 

Iraq, Somalia, Afghanistan and beyond, most of them women, children, and noncombatants. As a result, I travelled to Yemen and eventually to the United States, 

and I agreed with at least one person to carry an explosive device onto an aircraft 

and attempt to kill those on board and wreck the aircraft as an act of jihad against 

the United States for the U.S. killing of my Muslim brothers and sisters around 

the world. I was greatly inspired to participate in jihad by the lectures of the great 

and rightly guided mujahedeen who is alive, Sheikh Anwar al-Awlaki, may Allah 

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

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88

preserve him and his family and give them victory, Amin, and Allah knows best. 

Participation in jihad against the United States is considered among the most 

virtuous of deeds in Islam and is highly encouraged in the Koran; however, 

according to U.S. law, which is unjust and oppressive according to the Koran, my 

actions make me guilty of a crime in the United States, in particular, the following 

counts in my indictment... The United States – The United States should be 

warned that if they continue and persist in promoting the blasphemy of 

Muhammad and the prophets, peace be upon them all, and the U.S. continues to 

kill and support those who kill innocent Muslims, then the U.S. should await a 

great calamity that will befall them through the hands of the mujahideen soon by 

God’s willing permission. Or God will strike them directly with a great calamity 

soon by his will, Amin. If you laugh at us now, we will laugh at you later in this 

life and on the day of judgment by God’s will, and our final call is all praise to 

Allah, the lord of the universe, Allahu Akbar... The mujahedeen are proud to kill 

in the name of God, and that is exactly what God told us to do in the Koran.”

Scripting Solo Terrorist Events 

The solo terrorist script (Figure 5.2) appears similar to that of the lone actor terrorist 

script (Figure 5.1) except for the preparation phase which is ultimately simplified here 

through the pooling of social, technical and financial capital typically found within 

larger organizations. 

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

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89

Figure 5.2 Solo Actor Attack Script

Mass Murderers 

We now turn to a comparison group of offenders, mass murderers11, who like 

terrorists, engage (or attempt to engage in) largely public acts of violence and who 

often use similar weapons, but who are commonly distinguished from terrorists based 

on the absence of ideology. Our analysis of the 115 mass murderers in our unique 

dataset reveals that these offenders also differ from lone actor and solo actor terrorists 

in certain behaviors that typify their trajectory into violence.

In the first place, unlike lone and solo actor terrorist attacks, some mass murders 

appear to be spontaneous incidents, arising from the physical or emotional conflicts 

immediately prior to the attack and in which the individual does not exhibit any 

meaningful planning behaviors prior to the attack. While the percentage of mass 

 

11 Defined as an individual who kills four or more people in one event over a relatively short 

period of time (within 24 hours), excluding state sponsored or organized crime related events, 

or events that are solely domestic in nature

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
90

murders that occur in these circumstances (N = 17, 15%) is relatively small, the 

apparent lack of predetermined intent and strategy sets at least these offenders apart 

from lone actor and solo actor terrorists.

Nevertheless, like lone actor and solo actor terrorists, the majority of mass murderers 

(83%, N = 98) engage in a series of discreet, sequential behaviors that culminate in a

planned attack. In other words, most mass murders are the result of a process 

comprising a series of recognizable stages. A reasonable question, then, is whether 

the “script” that mass murderers follow is the same as the four-stage process we 

identified above for lone and solo terrorists. 

Below are five mass murder case studies that illustrate the ways in which mass 

murder might be described through the pathway to violence paradigm and which also 

highlight differences between mass murderers and lone actor terrorists as they move 

on a trajectory toward violence.

Kyle Huff 

On March 25, 2006 Kyle Aaron Huff attended a “zombie rave” in the Capitol Hill 

neighborhood in Seattle, Washington. There he was invited to an “after-rave” party 

which he attended hours later. The rave itself had heavy security, but some people, 

including Huff, continued the party afterward. Those who knew the 6’5 and 270-

pound Huff described him as a gentle giant. The manager of the apartment building 

where Huff lived said that the murders would have been “so far out of character” for 

Huff, describing Huff and his twin brother as “respectful” and good tenants. But in 

the early morning of that March day, this seemingly peaceful 28-year-old man briefly 

left the after-rave party, retrieved a shotgun and handgun from his truck parked 

around the block, paused to spray-paint the word “NOW” three times on the sidewalk, 

and began shooting as soon as he reached the house where the party was being held. 

He then walked methodically through the house, shooting through locked doors, and 

shouted “There’s plenty for everyone” (or something to that effect). He killed six 

partygoers (four males and two females) who ranged in age from 14 to 32, and 

seriously wounded two others. As the police arrived, Huff committed suicide.

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and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
91

Huff had moved to Seattle from Whitefish, Montana with his twin brother 

approximately four years before the mass murder. He had attended college but did 

not graduate, had been unemployed for several months before the event after several 

short stints as a pizza delivery driver, and was single. He had no known history of a 

diagnosed mental illness, and his criminal record was limited, with only a conviction 

for criminal mischief while he was living in Montana.

Grievance

At first, there was little evidence pointing to a motive for this seemingly random 

attack. The police were not able to establish any connection between Huff and any of 

the victims (other than attendance at the rave event) or between Huff and anyone who 

owned the private house where the shooting occurred. Further, the police did not 

uncover evidence of a dispute of any kind between Huff and anyone at the party, let 

alone the type of serious confrontation that might conceivably lead someone to feel 

the need to resort to deadly violence. 

Then, nearly a month after the murders and in a completely unrelated matter, the 

Seattle police responded to a report of a suspicious package found in a dumpster 

approximately a block from where Huff had lived in Seattle. The package itself was 

actually harmless, but what the police found in a fast-food bag in the dumpster shed 

new light on Huff’s mass murder. In the bag was a suicide note written by Huff two 

days before the attack. In the letter, addressed to his twin brother with whom he 

lived, Huff explained his motivation – defending society from the dangers of the raveculture that he perceived as dangerous and promiscuous. Huff wrote: “this is 

something I feel I have to do, my life would always feel in complete otherwise. I

can’t let them get away with what theyre doing, kids like me and you are seriously 

dying over this shit. I hate this world of sex that they are striving to make.” The 

presence of the letter in the dumpster has never been explained.

Some have speculated that the spray-painted words “NOW” may have been in 

reference to the “now, now, now, now” refrain from a popular song by the Seattle 

based band Nirvana, which was one of Huff’s favorite groups. Whether this was 

intended to provide a measure of insight into the motivation for the attack or was 

merely a troubled man paying homage a favorite group remains unknown.

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
92

Ideation

It is not possible to determine at what point Huff decided that mass murder was a 

reasonable approach to address his grievance. Neither his brother nor any of his 

friends in Montana or in Seattle can recall any signs that Huff would act violently and 

even those at the party that early morning had no indication that Huff was about to 

launch his attack. Huff is clear about his violent intent when he writes the suicide 

note, but the note does not provide any meaningful clues as to when he came to this 

violent ideation. It may have been as long as weeks before as he began attending rave 

parties, or at some even earlier time, although likely after he moved to Seattle.

Research and Planning

Subsequent to the finding of the suicide letter, the police investigation revealed that 

Huff had probably been planning the mass murder for longer than two days before the 

attack when he penned the suicide note. Apparently, Huff had been conducting 

surveillance on the rave community in Seattle for weeks. Some witnesses said that 

they saw Huff in his truck watching a rave in the beginning of February, nearly seven 

weeks before the murders. When the police searched Huff’s computer, they found 

searches related to the rave culture and a limited number of searches regarding a 

variety of hate groups. These searches do not seem to have been directly related to 

the planning of the mass murder.

Since he was invited to the party only once he was actually at the rave, it is not clear 

that Huff’s original plan had been to attack at that particular after-party. Based on the 

amount of ammunition he had with him in the truck, it could be that he intended to 

start shooting at the rave itself where there were many more potential targets. 

However, there were four guards at the rave checking for drugs and weapons, which 

might have discouraged Huff from attacking that site.

Preparation

While it is unclear exactly why Huff chose this particular party for his attack, it is 

clear that he was well-prepared for the event. Seattle Deputy Police Chief Clark 

Kimerer said that the slayings were definitely pre-meditated, noting that Huff had 

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

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93

loaded his truck with weapons and over 300 rounds of ammunition. Upon leaving the 

party, Huff retrieved a Winchester pump action 12-gauge shotgun and a Ruger P-94 

handgun, two bandoliers full of shotgun ammunition, and a tactical ammunition 

pouch holding AR-15 ammunition, even though he did not carry the AR-15 rifle back 

to the house, leaving it in the truck. Huff also left a machete and “flex-cuffs” in the 

truck, although it is not known if these items were related to the attack plan.

Breach

The breach in this case was both deadly and effective. Had he chosen to conceal his 

weaponry in some fashion, Huff likely could have simply walked back into the party 

he had voluntarily left moments earlier. Nevertheless, Huff took a more forceful 

approach, openly carrying his weapons through the street to the house. As he neared 

the front porch of the house, Huff immediately shot two of the victims, one of whom 

fell through the front doorway, which had an unintended effect on the breach. Several 

party-goers who heard the gunfire and had seen the two victims fall tried to push shut 

the front door but were unable to do so because the body of one of the victims was 

physically blocking the doorway. This allowed Huff to simple shove open the door 

and step over the victim’s body as he continued firing.

Attack

Somewhat curiously, Huff launched his attack as the party was winding down and 

many of the approximately 50 people who had attended the party had either left or 

were in the process of leaving. Had he began shooting a few hours before, he would 

likely have had even more targets to attack.

In any event, Huff was able to gain entry by shooting his way in. While his shooting 

pattern does show some evidence of disorganization, Huff had some measure of 

control as he began; noticing that the first two victims that he shot with the shotgun 

were still alive, he pulled out the pistol and shot each again. He went upstairs, came 

back downstairs, and then went into the basement. Along the way he discarded or 

dropped one bandolier, and when he stopped shooting, he walked back out the front 

door. The attack ended when Huff saw the police and shot himself in the head. 

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
94

Michael McDermott 

On December 26, 2000 Michael McDermott went to work at Edgewater Technologies 

in Wakefield, Massachusetts where he was a software tester, talked for some time 

with his co-workers, and then took out a semiautomatic rifle and shotgun and killed 

seven co-workers (four women and three men). Most of the victims worked in the 

human resources and accounting department of Edgewater Technologies. McDermott 

was apprehended on site and subsequently went to trial for the murders. His defense 

was that he was psychotic during the attack, believed that he had traveled back in time 

following instructions from God, and was actually shooting Nazis in Adolph Hitler’s 

bunker during 1940. He was convicted and sentenced to life in prison without the 

possibility of parole.

At the time, McDermott, who often went by “Mucko” (a nickname bestowed on him 

by his young nephews who could not pronounce his name), was 6’2, weighed over 

300 pounds, and had long, bushy beard. People at work thought he was reasonably 

amiable, but a bit peculiar. He lived by himself, and spent some of his free time 

posting on Internet bulletin boards, where he was known to have some expertise 

regarding explosives, although he did not make threatening posts or any that were 

considered politically volatile.

He had served six years in the United States Navy and was honorably discharged, 

never attended college, had no criminal convictions and no arrests prior to the mass 

murder. By 2000, he had been divorced for four years and lived alone. At trial, he 

presented evidence that as a young child a neighbor raped him repeatedly, and that he 

had attempted suicide several times as a teenager and as an adult. Approximately four 

years before the attack, McDermott was diagnosed with recurrent major depression, a 

mixed character disorder, and obsessive-compulsive personality. In the weeks before 

the mass murder, McDermott’s work performance suffered and he frequently showed 

up late for work.

Grievance

McDermott’s grievance - his belief that he was being treated unfairly by the human 

resources and accounting department at Edgewater - stemmed directly from the 

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
95

intersection of his mounting financial debts and efforts of the Internal Revenue 

Service to collect back-taxes. While a neighbor who lived upstairs from McDermott 

said that McDermott never mentioned any financial difficulties, McDermott was, in 

fact, continually in debt and was facing particularly acute financial stress around the 

time of the attack. In the months and years before the attack, McDermott was 

frequently late with his rent, and one landlord stated that McDermott moved out 

without paying over $1,600 in rent (which he never repaid).

The police investigation revealed that sometime in the month before the murders, the 

Internal Revenue Service contacted Edgewater Technologies and requested that they 

garnish McDermott’s wages. McDermott was upset about the company’s plan to 

comply with the IRS request. Additionally, on December 21st, just days before the 

shooting, McDermott learned that his car was going to be repossessed if he did not 

make his payments. 

Ideation

When employees in the accounting and human services department informed him of 

the planned garnishment, McDermott became explosively angry. It may have been at 

this time that McDermott settled on violence as a means of redress for what he 

considered unjust treatment. Additional evidence that McDermott settled on violence 

as a course of action is that at on December 22nd, four days before the event, 

McDermott asked several co-workers to sign as witnesses to a will he had prepared. 

This end-of-life planning, particularly since it was done at work, would seem to 

indicate that McDermott was at least contemplating a violent end for himself at 

approximately the same time that he was informed of the latest and most severe 

consequences of his financial instability – the garnishment of his wages and the 

potential loss of his car. 

Research and Planning

McDermott’s research and planning phase comprises two distinct areas. He not only 

carefully planned the attack, but he just as carefully planned his defense at trial. 

Knowing that surprise would be the key to killing as many of his targets as possible, 

McDermott stashed most of his weaponry in his work space the evening before 

(which was Christmas), when he stopped by Edgewater for a brief time (18 minutes) 

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
96

even though the offices were closed for the holiday. As for his claim at trial of 

psychosis, the prosecution countered by producing evidence that McDermott had used 

his personal computer to conduct research about how to fake mental illness. A record 

of his Internet searches showed that he had been constructing his legal defense at the 

same time that he was planning his mass murder. 

Preparation

McDermott was well prepared for his assault. He test-fired his shotgun and 

semiautomatic rifle two days before the attack, and dropped off weapons and 

ammunition in his work locker the day before the mass murder. On the day of the 

event, McDermott used a duffel bag to conceal the additional shotgun shells and 

cartridge boxes he was carrying. When police later searched his apartment, they 

found bomb-making materials, blasting caps, and three gallons of nitric acid, which 

can be used to make nitroglycerine. The investigation did not reveal any indication 

that McDermott intended to use those chemicals for any violent purpose.

Breach

McDermott’s breach was only that in the most technical sense, as he simply walked 

into work at his usual time and as expected. He chose to attack at a place where he 

knew the physical layout of the site and was confident that there would be no security 

measures that could defeat his intent. The targets he chose were also well known to 

him, as were their work schedules and their exact locations in the building. Thus, 

there was no need for him to use violence or deceit of any kind on the morning of the 

attack; in fact, any efforts to do so might have given his targets a warning of some 

kind and an opportunity to escape.

Attack

Part of McDermott’s method of attack was to rely on the usual routine of Edgewater. 

He arrived at work at 9:00 am and went about his normal activities. At 10:30 am he 

was in the company kitchen speaking with several co-workers. Those who were there 

recall that McDermott appeared to be unusually sociable, but that ceased when one of 

the co-workers began staring at the duffel bag McDermott was carrying. At 

approximately 11:07 am, McDermott received a telephone call from the repossession 

company about his car, and he stated that he no longer needed it and the repossession 

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
97

company could pick it up at the Edgewater garage. He also spoke by telephone with 

his mother. 

After the calls, McDermott returned to the lobby reception area carrying his duffel 

bag. When asked by the receptionist what he was doing, McDermott replied that he 

needed to see someone in human resources, and began firing, killing the receptionist 

and another co-worker. McDermott then walked to the accounting and human 

resources offices, bypassing several potential targets, and killing four more people as 

he went. In total, he fired more than three-dozen rounds from the semiautomatic rifle 

and shotgun.

When the police arrived, they found McDermott sitting silently in the lobby with his 

loaded weapons within reach. The defendant did not respond to police commands 

initially, stating: “I don’t speak German.” The police then arrested McDermott 

without incident.

Jeffrey Weise 

On March 21, 2005 16-year-old Weise killed his grandfather, who was a tribal law 

enforcement officer on the reservation where they lived, and his grandfather’s 

girlfriend, then drove to his school and opened fire at students and teachers in the 

hallways. He eventually killed nine people and wounded seven others. When law 

enforcement officers arrived, Weise engaged in a shootout before eventually 

retreating to a nearby classroom and killing himself. It appears that the victims at Red 

Lake High School were random. He did not leave a suicide note. 

Grievance

It is difficult to pinpoint what exactly motivated Weise to commit the murders, 

although is clear that he was troubled for many years before the murders. Jeffrey 

Weise had a difficult life from the time he was very young. Before Jeffrey was 

sixteen, his father had committed suicide and his mother was in a nursing home after 

suffering traumatic injuries in a car accident. After moving several times in his youth, 

he eventually moved in with his grandfather on the Red Lake Reservation in 

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
98

Minnesota. He was also a loner who was reportedly bullied at school, although 

apparently not to an extreme degree. By the time he was in high school he had been 

diagnosed with depression and had been prescribed increasingly higher doses of 

Prozac. 

An examination of his online posts show Weise admired Hitler, disapproved of “racial 

mixing”, and sometimes referred to himself online as the “Angel of Death” in German 

on various websites and chat rooms. He often drew comic books featuring images of 

people shooting each other and his sketch of a skeleton playing guitar accompanied 

by the words: “March to the death song ‘til your boots fill with blood” was displayed 

in his English classroom. Approximately 17 months prior to the mass murder, Weise 

pulled the eraser from a pencil and used the exposed metal edge to gouge his arm. 

Just a few months before the attack, he was reprimanded by a teacher at school and 

confined to a cubicle in the suspension room where he again gouged his arm. He was 

eventually expelled from school for violating rules, and at the time of the attack was 

in a program that provided tutoring at home. It may be that the accumulation of loss 

(of his father), rejection (by his peers), and his inability to connect with his mother (in 

a nursing home) propelled Weise toward extreme violence. 

Ideation

There is no clear indication of when Weise came to the decision to murder both 

family members and fellow students. Surviving family members believe that at least 

part of the explanation for Weise’s actions can be traced to a change in medication he 

was taking. The summer before the attack, Weise had attempted suicide, and 

afterward was put on a higher dose of the anti-depressant Prozac than he had been on 

before the attempt. Weise’s fascination with Nazis, seen in his computer searches and 

online postings and chats, indicate some attraction to violence as a solution to 

problems. And, he clearly seemed to understand that he was an angry and potentially 

dangerous person; in a profile page on an Internet site, Weise he described himself as 

"16 years of accumulated rage suppressed by nothing more than brief glimpses of 

hope, which have all but faded to black.” So, it appears that aside from being 

depressed and suicidal for years before the attack, Weise was also masking powerful 

feelings of anger (presumably) toward others whom he may have held responsible for 

his lot in life – including members of his family as well as his peers.

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
99

Research and Planning

Another teenager was arrested in connection with the mass murder, and is believed to 

have helped Weise plan the assault and reportedly also considered being part of the 

rampage. Both because Weise died in the attack and because of the status of both 

Weise and his alleged co-conspirator as minors, not all information regarding the 

planning of the attack has been made public. After a review of his emails though, law 

enforcement authorities concluded that Weise’s assault was not spontaneous and that 

he (and perhaps others) planned the event well in advance. 

Preparation

Weise was able to prepare for the mass murder in short order. He had everything he 

needed in his grandfather’s house – guns, ammunition, body armor, and 

transportation. Once he killed his grandfather and his grandfather’s girlfriend, he was 

fully prepared for his extensive assault on Red Lake High School. He would have 

known that he was barred from the school and that the (unarmed) security guard at the 

front door would challenge him. Weise was prepared for this circumstance, as he was 

armed and ready to shoot as he arrived at the school

Breach

Weise did not breach the first site of his attack, as he killed his grandfather and his 

grandfather’s girlfriend in the home that they all shared. Weise’s breach at Red Lake 

High school was violent and efficient. As he entered the school through a doorway 

with a metal detector he simply shot and killed the unarmed security guard who 

confronted him. Weise was then free to roam the hallways.

Attack

After killing his grandfather, who was a member of the tribal police force, Weise 

armed himself with his grandfather’s police-issued .40 caliber handgun, a 12-gauge 

shotgun, and his grandfather’s body armor vest before driving to the school in his 

grandfather’s police cruiser.

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
100

After killing the unarmed guard and gaining entry to the school lobby, Weise 

proceeded down a connected hallway. As he walked, Weise fired at a teacher and 

some students, who immediately fled into a classroom. Weise followed them into the 

classroom, killing the teacher and several of the students. He then continued down 

the hallway, apparently firing at random victims.

Four armed police officers entered the school and Weise fired on them as well. At 

least one officer returned fire, although it is not known if Weise was injured in that 

exchange. Shortly after this confrontation, Weise went into a classroom and shot 

himself in the head. During his attack, Weise fired 45 times, killing all of his victims 

at the school in less than three minutes, although he continued to wander the hallways 

shooting at random for approximately another six minutes.

Robert Hawkins 

On December 5, 2007 19-year-old Robert Hawkins walked into the Von Maur

department store at the Westroads mall in Omaha, Nebraska and started firing at 

shoppers with an AK-47-style semiautomatic rifle. He killed five women and three 

men, and injured two others. Finally, he killed himself. Hawkins had no known 

connection to any of the people he killed or wounded, and had no particular 

association with the mall itself (although it was only 20 miles from where he lived at 

the time and he had likely been there previously). 

Hawkins had a long history of drug use and troubling behavior, including a voluntary 

admission to a psychiatric treatment center after threatening to kill his stepmother 

when he was fourteen years old. While at this facility, Hawkins received private 

psychotherapy and drug counseling and eventually became a ward of the state when 

his family’s health insurance did not cover his continuing treatment. Hawkins lived 

in a variety of foster homes over the next several years, and was hospitalized at least 

twice more for psychiatric problems. He was eventually diagnosed with attentiondeficit disorder, oppositional defiant disorder, and mood disorder. 

At the time of the event, the state had terminated its custody, and Hawkins lived with 

the family of a friend after having been asked to leave the home of his latest foster 

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
101

parents. He was a high school dropout and his criminal record included being a minor 

in possession of an open container of alcohol, assault after a fight in high school, and 

possession with the intent to deliver drugs, and weeks before the mass murder he had 

been ticketed on suspicion of contributing to the delinquency of a minor and two 

alcohol charges. He had recently been fired from his job at a fast-food restaurant and 

broken up with his girlfriend.

Grievance

Hawkins had no known grievance with the people he killed or that mall where he 

attacked; his grievance appears to have been a more global one, driven both by his 

psychiatric and family history as well as by recent failures in his life. Since he 

committed suicide at the scene, the potentially complex ways in which these factors 

intersected and may have pushed Hawkins toward his murderous rampage will never 

be known with certainty.

Hours before the shooting, Hawkins called the house where he had been staying, 

speaking both with his friend and his friend’s mother and telling them that he was 

sorry and that they wouldn’t have to worry about him anymore. During that phone 

call, Hawkins revealed that he had just been fired from his job at McDonald’s, having 

been accused of stealing money from his till. After that phone call, the friend and the 

friend’s mother were worried that Hawkins was suicidal and they checked his room, 

discovering two suicide notes. The pair then called Hawkins’s biological mother, 

who came and picked up the notes and took them to the police.

Hawkins wrote one note to his family: 

Family, I’m so sorry for what I’ve put you through. I never meant to hurt all 

of you so much and I don’t blame any one of you for disowning me I just can’t

be a burden to you and my friends any longer. You are all better off without 

me. I’m so sorry for this.

I’ve just snapped I can’t take this meaningless existence anymore I’ve been a 

constant disappointment and that trend would have continued. just remember 

the good times we had together.

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102

That note ends with Hawkins expressing his love for his parents and various friends. 

There is no mention in the note of the attack at the mall.

The second note, which ends with a short will, is addressed to his friends, and begins 

much like the first note, expressing remorse for having caused trouble for his friends, 

having been a burden, and states that “this is the only option.” But, after requesting 

that his friends recall the many good times they managed to share, Hawkins writes 

something entirely different: Just think tho I’m gonna be fuckin famous. 

Approximately 40 minutes before the attack, Hawkins also texted a former girlfriend 

and said that he wanted to shoot a lot of people at a mall and then kill himself.

Ideation

Well before the mass murder Hawkins had revealed his violent ideation, not only 

threatening to kill his stepmother as a 14-year-old, but much more recently telling a 

friend that he would kill her and her family and burn their house down because he 

suspected her of stealing a CD player from his car. In addition to these specific 

instances of threatening murder, friends also say that Hawkins had been fixated on 

death for years and talked about it frequently.

As shown in the suicide note addressed to his friends, Hawkins saw violence not only 

as a means to address the frustration and despair that he was feeling, but also as a 

means to achieve a more general goal that had eluded him so far in his life – to 

become famous. Hawkins used mass murder as a means of forcing others to pay 

attention to him. 

Research and Planning

It is not possible to know how much time Hawkins spent planning his attack, but there 

is clear evidence that he did at least some minimal amount of research and planning. 

Even though he writes in his suicide notes that he “just snapped”, he obviously didn’t, 

as one of the notes shows that he had planned to kill not only himself, but also many 

others, at least enough to make him “famous.” It is unclear when Hawkins wrote the 

notes, but given his goal, it seems likely that Hawkins did at least enough research to 

know how many people he would have to kill in order to obtain the amount of media 

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
103

coverage that would qualify him, at least in his mind, as a famous person. Hawkins 

was also likely very much aware of the intense media coverage that Seung-Hui Cho 

received after the Virginia Tech shootings earlier that year. It is probable that he 

chose a location – the mall – precisely because it would be filled with holiday 

shoppers and would present a substantial number of targets, thereby increasing his 

chances of reaching his goal. 

Preparation

Hawkins did not have to invest significant time in preparing. He simply stole the rifle 

and ammunition from his stepfather. The day before the mass murder, Hawkins 

actually showed the rifle to the family with whom he was staying at the time. They 

did not think much of the weapon (which was apparently not in very good condition), 

and assumed that Hawkins was only going to target shoot or hunt, which would not 

have been unusual for him. 

Breach

While Hawkins had access to the mall during normal business hours, his method of 

entry was somewhat unusual and actually could have derailed his plan. Security 

video released by law enforcement shows Hawkins, wearing a hooded sweatshirt, 

entering the mall and looking around for a few moments before walking out and then 

coming back in the same door minutes later. This second time, he appears to be 

carrying something or have something hidden under his sweatshirt. He is then seen 

getting on an elevator. This unusual activity drew the attention of the unarmed mall 

security guards. It is unclear what actions the security guards took, but by the time 

police officers arrived minutes later in response to the shooting, Hawkins had already 

killed eight others and himself. 

Attack

Although the shooting actually began in the children’s department where Hawkins 

fired his rifle straight up in the ceiling, security photographs released by law 

enforcement show Hawkins standing on the balcony of the third floor of the mall, his 

sweatshirt unzipped and aiming the rifle at unseen targets. Hawkins then walked to 

the atrium where he leaned over an escalator railing and shot one man in the head. 

Hawkins next fired on people in front of a customer service counter, eventually 

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104

walking around to fire at those hiding behind the counter. He did not appear to target 

either specific people or a specific type of person; witnesses said it appeared that 

Hawkins was shooting at random targets, although he appeared to be aiming at people 

and not simply randomly shooting. The entire attack took only minutes, and was over 

by the time the first police officers arrived at the mall a little over five minutes after 

the first 911 call. Sounds of gunfire can be heard in the background of the call. The 

attack ended with Hawkins committing suicide.

Gang Lu 

On November 1, 1991 Gang Lu went on a shooting rampage at two separate buildings 

at the University of Iowa campus in Iowa City. Lu, who had recently earned his 

doctorate in physics from the school, killed four people and critically wounded two 

others before shooting himself in the head. 

A 28-year-old native of the People’s Republic of China, Lu was by all accounts a 

brilliant student who excelled in the study of physics. For six years, he had been one 

of the most gifted students in the nationally recognized department, specializing in 

space plasma theory. But he was also a loner, and others from the department who 

knew him said he lacked social skills and was isolated from his colleagues, including 

those from his native country who were also studying at the University of Iowa. He 

was single and had no known criminal record or mental health history. According to 

acquaintances, since graduation Lu had seemingly been under a greater than usual 

amount of pressure, most of it self-imposed. 

Grievance

Although many who succeed academically in competitive graduate departments are 

ambitious and hard-working, former professors described Lu as being extremely 

competitive; he was seen as someone who drove himself relentlessly toward academic 

achievement during his entire time at the university. Certain faculty members and 

fellow students also saw him as temperamental and easily agitated. A doctoral 

candidate who had been a roommate of Lu said that Lu “had a very bad temper and 

saw himself as No. 1. He had a psychological problem with being challenged.” This 

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
105

apparent need to be the best and to be perceived as the best led to Lu’s grievance 

aimed at the university. 

Although his dissertation regarding computer calculations of the properties of ionized 

glass impressed the faculty, Lu was extremely upset that he did not win an academic 

award for his dissertation. The prestigious Spriesterbach Dissertation Prize and the 

$2,500 that went with it were instead awarded to another student who had previously 

been Lu’s roommate. Ultimately, that student was one of the persons Lu specifically 

targeted and killed.

Subsequent to the attack, investigators recovered five letters written by Lu in which 

he reportedly identified his targets. None of the letters (four written in English and 

one in Chinese) were mailed before the attack. Lu had actually entrusted the letters to 

an acquaintance who was to mail them, but the acquaintance turned the letters over to 

the authorities after learning of the mass murder. Authorities said the letters 

described Lu’s grievance and outlined his detailed plans to kill even more university 

employees than he eventually did. The letters, though, make it clear that Lu’s 

grievance was primarily motivated by what he perceived to be slights to his academic 

reputation which he perceived would tar his professional reputation and prospects. 

Ideation

After failing to receive the dissertation award, Lu did not turn to violence 

immediately as a solution to his grievance. Instead, he first wrote a series of letters to 

the university appealing the departmental decision concerning the award of the

dissertation prize. None of these appeals succeeded, and Lu eventually dropped this 

non-violent approach. As indicated in his letters later recovered by the police, at 

some point after his written appeals were rejected, he consciously and deliberately 

decided to kill those he held responsible for his unjust treatment.

Research and Planning

The attack Lu carried out did not require extensive research or planning. At most, he 

needed to know where his targets would be on campus and he was likely able to 

establish their locations in advance of his attack. In addition, he attacked in locations 

with which he was very familiar and to which he had unfettered access. The 

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

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106

department meeting was a scheduled event and Lu would certainly have known that 

many, although not all, of his targets would be present. He also knew that he would 

be able to carry his handguns into the meeting, as there were no special security 

measures at this routine academic gathering. Once he was finished shooting at the 

meeting, Lu also knew exactly which other building on campus he needed to access in 

order to complete his task. He would have known how far the second building was 

from the first and how long it would take to walk from one to the next. In short, 

based on familiarity with the university and its personnel and procedures, Lu would 

have had little reason to conduct surveillance of any kind or commit time or resources 

to researching his targets and their schedules.

Preparation

Lu applied for a permit to buy a firearm in Iowa on May 21st, over five months before 

the mass murder. After showing his visa and Chinese passport, he was granted the 

permit three days later (although he legally owned the weapons, Lu did not have a 

permit to carry them). In addition to acquiring the means to carry out the attack, Lu 

also engaged in end-of life activities. Aside from giving letters explaining his actions 

to an acquaintance, Lu also mailed a package of personal belongings to his parents in 

China just an hour before the attack. When police searched his apartment, they 

concluded that Lu had taken the time to put his financial and personal affairs in order 

and had been preparing for the attack for some time.

Breach

Lu had no difficulty gaining entrance to the campus buildings for his attack. 

Although he was no longer a student at the University, he continued to work in a 

physics lab on campus as he sought employment. Thus, he had unfettered access to 

both buildings where he attacked, and his presence would have been unnoticed at the 

department meeting where he began the assault.

Attack

The shootings began at approximately 3:40 pm when Lu stood up during a scheduled 

meeting in his department and shot and killed four men. He did not say a word during 

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been published by the Department. Opinions or points of view expressed are those of the author(s) 

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107

the assault. The entire attack lasted less than 10 minutes, during which time Lu 

moved from the building where the meeting was being held to a nearby building 

where he continued firing. He appeared to specifically target certain people, shooting 

each victim at close range using a .38 caliber revolver. He also carried with him a .22 

caliber handgun that he did not fire. Once inside the second building, Lu eventually 

shot himself in the head, but was alive when police found him minutes after he fired 

his last shot.

In addition to murdering the student who received the dissertation award, Lu also 

killed three professors who were on his dissertation committee, including the 

chairman of the department. After walking the few block to the second building, he 

shot the vice president of academic affairs and her receptionist. After this, he walked 

upstairs to another floor where he shot himself. Lu eventually died from this selfinflicted gunshot.

Scripting Mass Murder Events 

Although still exploratory in nature, our examination of the 98 mass murderers in our 

dataset who do not engage in spontaneous violence reveals that they do not reliably 

follow the same “natural history from inception to completion” of the attack as lone 

actor and solo actor terrorists. 

Indeed, the fundamental distinction between the two groups – motivation – dictates 

different actuation points for violence. By definition mass murderers lack an ideology 

and, thus, cannot be said to engage in the decision and search activity involving 

calculations based on current “political and security climates” that characterizes the 

incipiency of lone actor and solo actor terrorist attacks. Most mass murderers (57%, 

N = 65) are concerned with personal feelings of having been wronged by a specific 

person and ultimately murder (or attempt to murder) the person whom they hold 

responsible for that wrong. Other mass murderers (16%, N = 18) have a grievance 

against a category of persons and attack representatives of that group (the remainder 

were either spontaneous attacks and/or any grievance is unknown).

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108

Nor do mass murderers typically concern themselves with post-event activity and 

strategic analysis as do lone actor and solo actor terrorists. The majority of mass 

murderer events are resolved when the offender commits suicide at the scene (43%, N 

= 50) or is killed by the police at the scene (10%, N = 12), and even those who 

survive appear not to have planned much beyond their homicidal attack. Very few 

displayed any evidence of having planned an escape (17%, N = 19) or having any 

intent to commit another attack (14%, N = 16). In short, it seems as if most mass 

murderers give very little attention to post-attack planning or strategizing of any kind. 

It is reasonable, then, to ask whether mass murderers follow a different “script” than 

do lone actor and solo actor terrorists. A model that may better describe the script of 

a mass murder has its origins in a behavioral pathway model conceptualized in two 

US Secret Service studies, one involving assassinations of public figures and the other 

school shootings (Fein & Vossekuil, 1999; Vossekuil et al., 2002). These and 

following studies theorized a route from idea to action comprising ideation, planning, 

preparation and implementation. These same phases were subsequently incorporated 

into an expanded model of a pathway to violence (Calhoun & Weston, 2003), which 

proposes the following six milestones: 

Grievance (the cause of the individual’s distress or resentment, often based on 

a perception – whether based in reality or not – of having been wronged or 

treated unfairly or inappropriately; resulting in a desire, even a sense of 

mission, to right the wrong and achieve a measure of deserved justice); 

Ideation (the point at which the individual realizes and accepts that violence 

is the appropriate and necessary means to address the grievance; the stage 

where the conscious choice is made to cause harm to others);

Research and Planning (at least a minimal amount of research and planning 

takes place once violence is adopted as the means to address the grievance, 

even if only to identify when an where the attack should take place; amount of 

research and planning can vary widely);

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Preparation (after a plan, however rudimentary is developed, the individual 

must acquire the means to carry out the plan; even if already possessing the 

weapon to be use, the person may need to acquire more or special 

ammunition, arrange transportation, etc.);

Breach (the step immediately prior to the attack in which the individual 

positions himself or herself for the assault and defeats any security measures 

in place, however minimal they might be); and 

Attack (the final stage where the intended plan for violence is enacted).

The five cases above provide illustrations of the pathway to violence paradigm, but 

they by no means cover the universe of experiences of those on a trajectory to 

perpetrate mass murder. Below, Table 5.1 outlines other examples taken from our 

unique dataset of 115 mass murderers of the behaviors for the six stages along the 

pathway to violence:

Table 5.1 Stages within the Pathway of Violence

Grievance

 Sense of being treated unfairly at work

 Desire for revenge for being bullied at school

 Belief in being unjustly denied fame

 Lack of success in forming romantic relationships

 Belief that a failing grade in high school resulted in 

adult unemployment

 Sense of being targeted for harassment by 

acquaintances and family

Ideation

 Communicating to third-parties the desire to harm 

others

 Dropping non-violent alternatives (appeals, 

lawsuits) to resolving grievance

 Identifying with Columbine murderers

 Contextually inappropriate use of firearms

 Fixation on militaristic gear and paraphernalia

 Generation of violent written content and images

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110

Research

& Planning

 Stalking 

 Surveillance of potential attack sites

 Practice approaches 

 Keeping a log of thoughts and information 

concerning the grievance

Preparation

 Acquiring weapons and/or ammunition

 Modifying weapons for ease of concealment or use

 Acquiring/arranging transportation

 Relatively minor “practice” aggressive acts

Breach

 Using a hostage to demand entry to attack site

 Shooting out doors/windows of a business

 Entering the lobby of a shopping mall

 Hiding a handgun in a backpack carried into work

 Dressing as a FedEx worker to gain entry to a home

Attack

 Taking children hostage at a schoolhouse 

 Randomly shooting at shoppers in mall

 Walking into work and attacking co-workers

 Setting fire to a crowded nightclub

 Killing a former spouse and bystanders at her place 

of work

 

This exploratory analysis suggests that mass murderers follow a different “script” 

than lone actor and solo actor terrorists as they move toward and through violence, 

and that the pathway to violence model offer a means of conceptualizing the process. 

We recognize that the pathway to violence model is just that – a model – and that 

there may be other relevant variables (such as the time between stages) that may have 

explanatory power. We do, though, see the model as a useful tool to integrate for 

further study the behaviors that typically compose the phenomenon of mass murder. 

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6. Conclusion 

On the surface, both lone actor terrorism and mass murder attacks seem to defy 

explanation. The immediate aftermath of both phenomena is marked by drama, panic 

and an inevitable search for simple answers. In particular, there is an unerring 

tendency to reach for mono-causal master narrative explanations. We can consider 

President Obama’s words on lone actors as an illustration: 

The biggest concern we have right now is not the launching of a major 

terrorist operation...the risk that we’re especially concerned over right now is 

the lone wolf terrorist, somebody with a single weapon being able to carry out 

wide-scale massacres...You know, when you’ve got one person who is 

deranged or driven by a hateful ideology, they can do a lot of damage 

(emphasis added - http://security.blogs.cnn.com/2011/08/16/obama-biggestterror-fear-is-the-lone-wolf/) 

“Deranged or driven by a hateful ideology” is a perfect example of two master 

narratives that are often proffered and treated as being mutually exclusive. The 

individual actor is either deranged, unbalanced, unhinged, disturbed, mad, crazy, nuts 

and unstable, or he/she is driven by a hateful ideology, radicalized, politically 

focused, inspired by some foreign ‘entity’, or determined to effect some social or 

political upheaval or policy change. In the days that follow an event such as these, the 

framing of the individual’s motivation usually takes on one of these two narratives. 

The chosen narrative depends upon the easy availability of information regarding 

their ideological content, mental health history or personal background details. 

Yet what we see from the analysis we offer here, lone actor terrorism and mass 

murderer attacks are (both) usually the culmination of a complex mix of personal, 

political and social drivers that crystalize at the same time to drive the individual 

down the path of violent action. Whether the violence comes to fruition is usually a 

combination of the availability and vulnerability of suitable targets that suit the heady 

mix of personal and political grievances and the individual’s capability to engage in 

an attack from both a psychological and technical capability standpoint. Many 

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individual cases share a mixture of unfortunate personal life circumstances coupled 

with an intensification of beliefs that later developed into the idea to engage in 

violence. What differed was how these influences were sequenced. Sometimes 

personal problems led to a susceptibility to ideological influences. Sometimes longheld ideological influences became intensified after the experience of personal 

problems. This is why we should be wary of mono-causal master narratives. The 

development of these behaviors is usually far more labyrinthine and dynamic. 

One of the major implications of comparative analyses such as this could be to 

provide guidance or a framework to those tasked with responding to such phenomena. 

Given our counter-intuitive findings on the leakage of intent, this may be particularly 

relevant in terms of early disruption of plots. An understanding of this complexity and 

the multiplicity of potential factors could help inform how threat assessments of 

particular lone actors should be carried out. When we talk about ‘threat’, and the 

related concept of risk, we need to consider multiple, overlapping questions including 

issues related to identification of threats (e.g. threat of what precisely?), exposure (e.g. 

under what conditions are particular offences more likely?) and management (i.e. 

which interventions are likely to be effective in terms of mitigating either risk, 

broadly speaking, or a specific threat) (Borum, 1999). The illustrations highlight that 

the target and/or target location of the violence was usually associated with something 

to do with the individual’s personal grievance. This may help give us a sense of what 

Borum calls the ‘scenarios of exposure’ or the conditions under which a particular 

individual become a threat. The temporal issues also highlight the fact that we need to 

view risk dynamically. Given a set of circumstances and conditions an individual may 

appear to be no or low risk. However, small changes in their life-course, personal 

circumstances or opportunity to offend can have a force-multiplier effect and propel 

the individual into a higher category of risk. These issues are explored in detail by 

Monahan (2012) who warns however, of the need for comparison samples (including 

control groups) in order to scientifically validate many of the otherwise working 

assumptions relevant to risk assessment. 

From the analysis presented in this paper, however, the actual violence conducted by 

lone actors and mass murderers looks very similar. We sought to examine whether 

their ‘radicalization’ trajectory toward this act of violence was also similar. The 

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analyses suggest that they share a lot in common but significant differences persist. 

This has a multiplicity of implications for early detection, threat management and 

possibly disruption. The job of intelligence analysts (be it for the police or 

intelligence communities) often involves assessing the scale of an individual’s threat 

based on often fragmentary information. The analyses above do not point toward one 

single behavioral profile from which risk assessments can be built. They do however, 

help frame the types of questions that intelligence analysts can ask to get a fuller 

picture of the threat. In a later deliverable for this project, we return to this issue by 

examining how behaviors cluster together across a sizeable number of individuals 

(both lone actors and mass murderers). The results also highlight the fact that (a) in 

most cases there tends to be long-held risk factors but (b) they tend to be enabled in a 

force multiplier effect by much more recent situational stressors and that (c) the 

trajectory into violence tends to be a lengthy process. Phases may be identifiable on 

this process, from grievance formation to fixation to capacity building to attack 

planning. If an individual is identified ahead of time (say for example after leaking 

key information), the individual’s position in this pathway can be plotted, and a range 

of disruption/prevention tools can be implemented from there. 

In terms of indicators, the vast majority of lone actor terrorists each demonstrated 

elements concerning (a) their grievance, (b) an escalation in their intent to act, (c) 

gaining capability – both psychologically and technically and (d) attack planning (see 

Figure) 6.1. 

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Figure 6.1: Threat Assessment Framework 

Finally, the routine activity studies also provided much insight from a disruption and 

prevention perspective. Much of the anxiety concerning the threat of lone actor 

terrorism stems from concerns regarding the ability to detect and intercept lone actor 

terrorist events before they occur. Traditional methods employed against formal 

terrorist organizations and loosely connected terrorist networks (such as counterintelligence, HUMINT, interception of communications, surveillance of persons, 

targeted killing etc.) may not be as readily applicable against the threat of lone actor 

terrorists. Strategies aimed at countering radicalization in the community may have no 

reference point in identifying lone at-risk individuals. Deterrence measures also may 

prove problematic for countering lone actor terrorism. Because prediction and 

identification are difficult, it might be better to instead guard against future lone actor 

terrorists by making the actual undertaking of a terrorist attack more difficult. For 

example, it might be easier and more cost-efficient to deter a budding lone actor 

terrorist by making it more difficult to acquire the necessary bomb-making materials 

than by convincing him/her of counter-narratives. 

In terms of future research, there are a myriad number of ways to improve our 

understanding. First, there has been next to no rigorous research involving interviews 

with lone actor terrorists or mass murderers. We are therefore lacking in a particularly 

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rich source of information, not only on radicalization, attack planning and attack 

commission, but also issues surrounding deradicalization and disengagement. Second, 

on only a couple of the key factors do we have a sense of societal base rates. An 

ambitious program of work is needed to assess how different prevalence rates of risk 

factors and their co-occurrence are against the rates found within wider society. Third, 

sequencing analysis like those used in chapter five do not necessarily have to involve 

thick qualitative case studies but can utilize quantitative approaches (like State 

Transition Diagrams). What has held the field back for so long is the lack of data but 

that is becoming increasingly less of an issue. Finally, this study (and most of the 

associated field) is reliant upon open-source data. Closer collaboration between 

academics and law enforcement agencies tasked with responding to these threats is 

needed. This relationship is not necessarily uni-directional (e.g. academics help 

practitioners) but can be a two way process where practitioners actively relay the 

operational difficulties they face and the practical questions they feel need addressing. 

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116

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and do not necessarily reflect the official position or policies of the U.S. Department of Justice.
121

 

This document is a research report submitted to the U.S. Department of Justice. This report has not 

been published by the Department. Opinions or points of view expressed are those of the author(s) 

and do not necessarily reflect the official position or policies of the U.S. Department of Justice.