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entitled 'Information on Certain Illegal Aliens Arrested in the United 
States' which was released on May 9, 2005. 

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United States Government Accountability Office:

Washington, DC 20548:

May 9, 2005:

The Honorable John N. Hostettler: 
Chairman, Subcommittee on Immigration, Border Security, and Claims: 
Committee on the Judiciary: 
House of Representatives:

The Honorable Steve King: 
House of Representatives:

The Honorable Melissa Hart: 
House of Representatives:

Subject: Information on Certain Illegal Aliens Arrested in the United 
States:

The former Immigration and Naturalization Service estimated that as of 
January 2000 the total unauthorized immigrant population residing in 
the United States was 7 million.[Footnote 1] This total includes those 
who entered the United States illegally and those who entered legally 
but overstayed their authorized period of stay. A more recent study 
estimated that there were about 10 million illegal aliens living in the 
United States as of March 2005.[Footnote 2] The study estimated that 
nearly 700,000 aliens entered the United States illegally or overstayed 
their authorized period of stay each year between 2000 and 2004. Some 
illegal aliens in the United States have been arrested and incarcerated 
in federal and state prisons and local jails, adding to already 
overcrowded prisons and jails. 

On April 7, 2005, we issued a report on criminal aliens[Footnote 3] 
that were incarcerated in federal and state prisons and local 
jails.[Footnote 4] Our report contained information on the number of 
criminal aliens incarcerated, their country of citizenship or country 
of birth, and the cost to incarcerate them. You also requested that we 
provide information on the criminal history of aliens incarcerated in 
federal and state prisons or local jails who had entered the country 
illegally. For a population of aliens that entered the country 
illegally and were incarcerated in federal or state prisons or local 
jails, this report addresses the following questions:

* How many times have they been arrested?

* How many and what type of criminal offenses have they been arrested 
for?

* What states were they arrested in?

To obtain information to answer these objectives, we identified a 
population of 55,322 aliens that the U.S. Immigration and Customs 
Enforcement (ICE) in the Department of Homeland Security determined, 
based upon information in its immigration databases, had entered the 
country illegally and were still illegally in the country at the time 
of their incarceration in federal or state prison or local jail during 
fiscal year 2003. We then analyzed selected data contained in the 
criminal history record, commonly referred to as the rap sheet, of 
these illegal aliens maintained within the Federal Bureau of 
Investigation's (FBI) Integrated Automated Fingerprint Identification 
System (IAFIS).[Footnote 5] To assess the reliability of immigration 
databases used to make the determination about an alien's legal status, 
we discussed internal control processes for ensuring data quality with 
responsible ICE staff and found the data to be reliable for purposes of 
this report. To assess the reliability of IAFIS data, we discussed the 
data collection methods and internal control processes for ensuring 
data quality with responsible FBI staff and reviewed relevant policies 
and procedures. IAFIS may not contain all of the arrests for the 
illegal aliens in our study population since seven states report only 
their first arrest to the FBI. Subsequent arrest data is available only 
from the state's criminal history record system. While the magnitude of 
any undercount is unknown, we found that the data we used for our 
analyses were sufficiently reliable for the purposes of this report. 

Several things should be noted regarding our analysis. First, an arrest 
does not necessarily result in a prosecution or a conviction. Second, 
our analysis is limited to the aliens that ICE determined to have 
entered the United States illegally. Third, since all arrests for an 
individual may not be recorded in IAFIS, our data represent the minimum 
number of arrests for these illegal aliens. Last, our analysis is not 
designed to infer conclusions about the arrest history of other illegal 
aliens not in our study population who entered the country illegally 
and have been arrested. 

In April, we discussed with your offices the results of our work. This 
report conveys the information provided during those discussions (see 
encl. I). 

We performed our work from October 2004 through May 2005 in accordance 
with generally accepted government auditing standards. Further details 
on our scope and methodology, including how we selected the illegal 
aliens in our study population, are discussed in enclosure II. 

Results:

The briefing slides in enclosure I address each of our three questions. 
In summary, for our study population of 55,322 illegal aliens, we found 
that:

* They were arrested at least a total of 459,614 times, averaging about 
8 arrests per illegal alien. Nearly all had more than 1 arrest. Thirty-
eight percent (about 21,000) had between 2 and 5 arrests, 32 percent 
(about 18,000) had between 6 and 10 arrests, and 26 percent (about 
15,000) had 11 or more arrests. Most of the arrests occurred after 
1990. 

* They were arrested for a total of about 700,000 criminal offenses, 
averaging about 13 offenses per illegal alien. One arrest incident may 
include multiple offenses, a fact that explains why there are nearly 
one and half times more offenses than arrests.[Footnote 6] Almost all 
of these illegal aliens were arrested for more than 1 offense. Slightly 
more than half of the 55,322 illegal aliens had between 2 and 10 
offenses. About 45 percent of all offenses were drug or immigration 
offenses. About 15 percent were property-related offenses such as 
burglary, larceny-theft, motor vehicle theft, and property damage. 
About 12 percent were for violent offenses such as murder, robbery, 
assault, and sex-related crimes. The balance was for such other 
offenses as traffic violations, including driving under the influence; 
fraud--including forgery and counterfeiting; weapons violations; and 
obstruction of justice. 

* Eighty percent of all arrests occurred in three states--California, 
Texas, and Arizona. Specifically, about 58 percent of all arrests 
occurred in California, 14 percent in Texas, and 8 percent in Arizona. 

Agency Comments and Our Evaluation:

The Departments of Justice and Homeland Security reviewed a draft of 
this report and had technical comments, which we incorporated as 
appropriate. 

We are sending copies to the Departments of Justice and Homeland 
Security and interested congressional committees, and we will make 
copies available to others who request them. In addition, the report 
will be available at no charge on GAO's Web site at http://www.gao.gov. 

If you or your staff have any questions concerning this report, please 
contact me at (202) 512-8816 or by e-mail at Stanar@gao.gov or Michael 
Dino, Assistant Director, at (213) 830-1150 or Dinom@gao.gov. Key 
contributors to this report were Amy Bernstein, Ann H. Finley, Evan 
Gilman, Frederick Lyles, Jr., Jan Montgomery, Karen O'Conor, Jason 
Schwartz, and Laura Czohara. 

Sincerely yours,

Signed by: 

Richard M. Stana, 
Director, Homeland Security and Justice Issues:

[End of section]

Enclosure I: Briefing Slides:

Information on Certain Illegal Aliens Arrested in the United States: 

Briefing for Congressional Requesters: 
April 2005: 

Introduction: 

In April 2005, we issued a report, Information on Criminal Aliens 
Incarcerated in Federal and State Prisons and Local Jails, (GAO-05-
337R). This report contained information on the number of criminal 
aliens we identified that were incarcerated, their country of 
citizenship or country of birth, and the cost to incarcerate them. 

You also requested that we provide information on the criminal history 
of aliens incarcerated in federal and state prisons or local jails who 
had entered the country illegally. 

Objectives: 

For a population of aliens incarcerated in federal and state prisons 
and local jails during fiscal year 2003 who entered the country 
illegally, we address the following questions:

(1) How many arrests did they have? 

(2) How many and what type of criminal offenses have they been arrested 
for?

(3) What states were they arrested in? 

Results in Brief: How many arrests did these illegal aliens have? 

For our study population of 55,322 illegal aliens:

* They were arrested at least a total of 459,614 times, averaging about 
8 arrests per illegal alien.[Note 1]

* Ninety-seven percent had more than 1 arrest. About 38 percent had 
between 2 and 5 arrests, 32 percent had between 6 and 10 arrests, and 
26 percent had over 11 arrests.

* Eighty-one percent of all arrests occurred after 1990.

[1] An arrest does not necessarily result in a prosecution or a 
conviction.

Results in Brief: How many and what type of criminal offenses were they 
arrested for? 

For our study population of 55,322 illegal aliens:

* They were arrested for at least a total of nearly 700,000 criminal 
offenses, averaging 13 offenses per alien.

* About 24 percent were drug offenses.

* About 21 percent were immigration offenses.

* About 15 percent were property-related offenses such as burglary, 
larceny-theft, motor vehicle theft, and property damage.

* About 12 percent were for murder, robbery, assault, and sexually 
related crimes.

* The remaining 28 percent were for other offenses such as traffic 
violations, including driving under the influence; fraudincluding 
forgery and counterfeiting; weapons violations; and obstruction of 
justice.

Results in Brief: What states were they arrested in?

For our study population of 55,322 illegal aliens:

* Eighty percent of all arrests occurred in the following 3 states.

California: 58 percent.

Texas: 14 percent.

Arizona: 8 percent. 

Background: 

When an individual is taken into custody, the arresting law enforcement 
agency captures the arrest charge(s), fingerprints, and personal 
identifiers of the individual. This information is submitted to the 
FBIs Integrated Automated Fingerprint Identification System (IAFIS), 
which is responsible for preserving identification and criminal history 
records for felony and serious misdemeanor offenses. The FBI assigns an 
FBI identification number to each set of fingerprints. 

Generally, all aliens arrested by the DHSs U.S. Immigration and 
Customs Enforcement (ICE) are assigned an alien identification number. 
This allows ICE to establish and track an aliens immigration history. 

For illegal aliens incarcerated in state prisons and local jails, the 
federal government has reimbursed state and local governments that 
apply for reimbursement for a portion of their incarceration costs 
through the Department of Justices (DOJ) State Criminal Alien 
Assistance Program (SCAAP), managed by the Bureau of Justice Assistance 
(BJA).

Scope and MethodologyStudy Population of Illegal Aliens Used in Our 
Analysis: 

Number of convicted criminal aliens; 
Inmates incarcerated in federal prison on December 27, 2003: 46,063; 
Inmates incarcerated by state prisons and local jails and submitted to 
SCAAP for reimbursement[NOTE 1]: 262,105. 

Number of unique convicted criminal aliens with a FBI identification 
number and an alien identification number 
Inmates incarcerated in federal prison on December 27, 2003: 36,390; 
Inmates incarcerated by state prisons and local jails and submitted to 
SCAAP for reimbursement[NOTE 1]: 59,427. 

Number of the above unique convicted criminal aliens that ICE 
determined to have entered illegally; 
Inmates incarcerated in federal prison on December 27, 2003: 18,581; 
Inmates incarcerated by state prisons and local jails and submitted to 
SCAAP for reimbursement[NOTE 1]: 36,741. 

Total study population of illegal aliens used in our analysis: 55,322.

[1] These represent the inmates incarcerated in state prisons and local 
jails between July 1, 2002, and June 30, 2003. 

[End of table]

Scope and MethodologyAnalysis of Arrest Data: 

* For the 55,322 illegal aliens in our study population, we obtained 
and analyzed the arrest history information contained in IAFIS as of 
October 2004.

* The arrest history information contained the date of arrest; the 
arresting federal, state, or local law enforcement agency; and a 
narrative description of the offense for which the alien was arrested. 

* For purposes of our analysis, we categorized these arrest 
descriptions into 1 of 19 major offense categories, e.g., immigration, 
drugs (see slides 10 and 11).

* In addition, for the 18,581 illegal aliens in our study population 
who were incarcerated in a federal prison, we analyzed related 
conviction information.

Note: Under 28 U.S.C. 534, the FBI is required to acquire, collect, 
classify, and preserve, among other things, identification and criminal 
records. IAFIS includes individuals who have been arrested for an 
offense that is classified as a felony or a serious misdemeanor.

Scope and MethodologyCrimes Included in Major Offense Categories: 

Major offense category[1]: Arson; 
Category includes: arson, reckless burning, and possession of arson 
materials. 

Major offense category[1]: Assault; 
Category includes: assault, battery, assault with a deadly weapon, 
endangerment, and threats. 

Major offense category[1]: Burglary; 
Category includes: breaking and entering, burglary, and possession of 
burglary tools. 

Major offense category[1]: Disorderly conduct; 
Category includes: disturbing the peace, fighting, intoxication, public 
nuisance, and disorderly conduct. 

Major offense category[1]: Drugs; 
Category includes: use/under the influence, possession, possession with 
intent to distribute, sales, manufacturing, transporting, and 
possession of drug paraphernalia. 

Major offense category[1]: Fraud, forgery, and counterfeiting; 
Category includes: deceptive practices or identification, fraud, giving 
false information, altering or forging documents, and counterfeiting or 
possession of counterfeit materials or tools. 

Major offense category[1]: Homicide; 
Category includes: murder, manslaughter, and homicide. 

Major offense category[1]: Immigration; 
Category includes: illegal entry, illegal reentry, false claim to U.S. 
citizenship, alien smuggling, and removal proceedings. 

Major offense category[1]: Kidnapping; 
Category includes: false imprisonment, kidnapping, and taking hostages. 

Major offense category[1]: Larceny/theft; 
Category includes: grand and petty larceny and theft, shoplifting, 
embezzlement, and money laundering. 

Major offense category[1]: Motor vehicle theft; 
Category includes: auto theft, carjacking, and taking a vehicle without 
consent. 

Major offense category[1]: Obstruction of justice; 
Category includes: escaping, evading, being a fugitive of justice, 
failing to appear, failing to register as a sex offender, resisting 
arrest, and interfering with or obstructing an officer or justice 
proceedings. 

Major offense category[1]: Property damage; 
Category includes: destruction of property, vandalism, and criminal or 
malicious mischief. 

Major offense category[1]: Robbery; 
Category includes: armed robbery, robbery of a dwelling, robbery of a 
bank, and unarmed robbery. 

Major offense category[1]: Sex offenses; 
Category includes: lewd and lascivious acts, rape, sexual assault, 
indecent exposure, prostitution, and molestation. 

Major offense category[1]: Stolen property; 
Category includes: buying, selling, receiving, or possessing stolen 
property. 

Major offense category[1]: Traffic violations; 
Category includes: driving under the influence, hit and run, no proof 
of insurance, no drivers license, and moving violations such as 
speeding and failure to stop. 

Major offense category[1]: Weapons violations; 
Category includes: possession of a weapon, discharging a weapon, 
altering a weapon, and carrying a concealed weapon. 

Major offense category[1]: Other; 
Category includes: includes trespassing, gang participation, littering, 
child cruelty, racketeering, and illegal waste dumping.

[1] All offenses include any attempt or conspiracy to commit the 
respective offense. We developed the criminal offense categories using 
the FBIs classification for offense codes as our guidance. 

[End of table]

Data Limitations: 

* The FBIs IAFIS does not include all arrests and offenses7 
states[note 1] report only the first arrest and associated offenses to 
the FBI, subsequent arrest information is available only through the 
states criminal history database. Further, some law enforcement 
agencies do not report information on every arrest to the FBI. Also, 
IAFIS does not include minor misdemeanor offenses.

* FBI may reject fingerprint cards that are not readable, and sometimes 
the submitting law enforcement agency does not resubmit the card for 
entry into IAFIS.

* Results of our analysis pertain only to our study population. Results 
cannot be generalized to all illegal aliens that may have been arrested 
and therefore cannot be interpreted as representing arrest or offense 
rates for all illegal aliens. 

NOTE 1: Colorado, Florida, Montana, Oklahoma, Oregon, New Jersey, and 
North Carolina.

Number of Arrests: 
Ninety-seven percent of illegal aliens in our study population had more 
than one arrest: 

[See PDF for image]

[End of figure]

Number of Arrests: Federal Prison Inmates: Ninety-nine percent of 
incarcerated illegal aliens had more than one arrest: 

[See PDF for image]

[End of figure]

Number of Arrests: State Prison and Local Jail Inmates: Ninety-six 
percent of incarcerated illegal aliens had more than one arrest: 

[See PDF for image]

[End of figure]

Arrest Offenses: Illegal aliens in our study population were arrested 
for almost 700,000 offenses, averaging 13 offenses per illegal 
alien[A]: 

* Number of illegal aliens in our study population: 55,322.

* Total number of arrests[B]: 459,614. 

* Total number of criminal offenses: 691,890.

* Average number of criminal offenses per illegal alien: 13.

* Median number of criminal offenses per illegal alien: 10. 

[A] One arrest incident may include multiple offenses. 

[B] For the study population of illegal aliens, the analysis time frame 
covers arrests recorded in the FBIs IAFISdating from 1947 to October 
28, 2004.

Source: GAO analysis of FBI IAFIS data.

[End of table]

Number of Offenses: Ninety-eight percent of illegal aliens in our total 
study population were arrested for two or more offenses: 

[See PDF for image]

[End of figure]

Arrest Offenses: Forty-five percent of illegal alien offenses were for 
drugs and immigration: 

Criminal offense: Drugs; 
Total offenses: Number: 166,722; 
Total offenses: Percent: 24%; 
Offenses for illegal aliens in federal prisons: Number: 64,737; 
Offenses for illegal aliens in federal prisons: Percent: 24%; 
Offenses for illegal aliens in state prisons and local jails: Number: 
101,985; 
Offenses for illegal aliens in state prisons and local jails: Percent: 
24%. 

Criminal offense: Immigration; 
Total offenses: Number: 144,166; 
Total offenses: Percent: 21%; 
Offenses for illegal aliens in federal prisons: Number: 84,382; 
Offenses for illegal aliens in federal prisons: Percent: 32%; 
Offenses for illegal aliens in state prisons and local jails: Number: 
59,784; 
Offenses for illegal aliens in state prisons and local jails: Percent: 
14%. 

Criminal offense: Traffic violations; 
Total offenses: Number: 55,060; 
Total offenses: Percent: 8%; 
Offenses for illegal aliens in federal prisons: Number: 13,290; 
Offenses for illegal aliens in federal prisons: Percent: 5%; 
Offenses for illegal aliens in state prisons and local jails: Number: 
41,770; 
Offenses for illegal aliens in state prisons and local jails: Percent: 
10%. 

Criminal offense: Assault; 
Total offenses: Number: 50,958; 
Total offenses: Percent: 7%; 
Offenses for illegal aliens in federal prisons: Number: 14,908; 
Offenses for illegal aliens in federal prisons: Percent: 6%; 
Offenses for illegal aliens in state prisons and local jails: Number: 
36,050; 
Offenses for illegal aliens in state prisons and local jails: Percent: 
8%. 

Criminal offense: Obstruction of justice; 
Total offenses: Number: 45,632; 
Total offenses: Percent: 7%; 
Offenses for illegal aliens in federal prisons: Number: 15,064; 
Offenses for illegal aliens in federal prisons: Percent: 6%; 
Offenses for illegal aliens in state prisons and local jails: Number: 
30,568; 
Offenses for illegal aliens in state prisons and local jails: Percent: 
7%. 

Criminal offense: Burglary; 
Total offenses: Number: 38,689; 
Total offenses: Percent: 6%; 
Offenses for illegal aliens in federal prisons: Number: 13,156; 
Offenses for illegal aliens in federal prisons: Percent: 5%; 
Offenses for illegal aliens in state prisons and local jails: Number: 
25,533; 
Offenses for illegal aliens in state prisons and local jails: Percent: 
6%. 

Criminal offense: Larceny/theft; 
Total offenses: Number: 31,883; 
Total offenses: Percent: 5%; 
Offenses for illegal aliens in federal prisons: Number: 12,206; 
Offenses for illegal aliens in federal prisons: Percent: 5%; 
Offenses for illegal aliens in state prisons and local jails: Number: 
19,677; 
Offenses for illegal aliens in state prisons and local jails: Percent: 
5%. 

Criminal offense: Fraud, forgery, and counterfeiting; 
Total offenses: Number: 25,773; 
Total offenses: Percent: 4%; 
Offenses for illegal aliens in federal prisons: Number: 8,564; 
Offenses for illegal aliens in federal prisons: Percent: 3%; 
Offenses for illegal aliens in state prisons and local jails: Number: 
17,209; 
Offenses for illegal aliens in state prisons and local jails: Percent: 
4%. 

Criminal offense: Weapons violations; 
Total offenses: Number: 22,263; 
Total offenses: Percent: 3%; 
Offenses for illegal aliens in federal prisons: Number: 7,236; 
Offenses for illegal aliens in federal prisons: Percent: 3%; 
Offenses for illegal aliens in state prisons and local jails: Number: 
15,027; 
Offenses for illegal aliens in state prisons and local jails: Percent: 
4%. 

Criminal offense: Motor vehicle theft; 
Total offenses: Number: 20,950; 
Total offenses: Percent: 3%; 
Offenses for illegal aliens in federal prisons: Number: 6,494; 
Offenses for illegal aliens in federal prisons: Percent: 2%; 
Offenses for illegal aliens in state prisons and local jails: Number: 
14,456; 
Offenses for illegal aliens in state prisons and local jails: Percent: 
3%. 

Criminal offense: Robbery; 
Total offenses: Number: 15,305; 
Total offenses: Percent: 2%; 
Offenses for illegal aliens in federal prisons: Number: 4,177; 
Offenses for illegal aliens in federal prisons: Percent: 2%; 
Offenses for illegal aliens in state prisons and local jails: Number: 
11,128; 
Offenses for illegal aliens in state prisons and local jails: Percent: 
3%. 

Criminal offense: Stolen property; 
Total offenses: Number: 13,415; 
Total offenses: Percent: 2%; 
Offenses for illegal aliens in federal prisons: Number: 4,201; 
Offenses for illegal aliens in federal prisons: Percent: 2%; 
Offenses for illegal aliens in state prisons and local jails: Number: 
9,214; 
Offenses for illegal aliens in state prisons and local jails: Percent: 
2%. 

Criminal offense: Sex offense; 
Total offenses: Number: 11,833; 
Total offenses: Percent: 2%; 
Offenses for illegal aliens in federal prisons: Number: 2,501; 
Offenses for illegal aliens in federal prisons: Percent: 1%; 
Offenses for illegal aliens in state prisons and local jails: Number: 
9,332; 
Offenses for illegal aliens in state prisons and local jails: Percent: 
2%. 

Criminal offense: Disorderly conduct; 
Total offenses: Number: 8,768; 
Total offenses: Percent: 1%; 
Offenses for illegal aliens in federal prisons: Number: 2,986; 
Offenses for illegal aliens in federal prisons: Percent: 1%; 
Offenses for illegal aliens in state prisons and local jails: Number: 
5,782; 
Offenses for illegal aliens in state prisons and local jails: Percent: 
1%. 

Criminal offense: Property damage; 
Total offenses: Number: 6,478; 
Total offenses: Percent: 1%; 
Offenses for illegal aliens in federal prisons: Number: 2,238; 
Offenses for illegal aliens in federal prisons: Percent: 1%; 
Offenses for illegal aliens in state prisons and local jails: Number: 
4,240; 
Offenses for illegal aliens in state prisons and local jails: Percent: 
1%. 

Criminal offense: Homicide; 
Total offenses: Number: 5,992; 
Total offenses: Percent: 1%; 
Offenses for illegal aliens in federal prisons: Number: 1,156; 
Offenses for illegal aliens in federal prisons: Percent: <1%; 
Offenses for illegal aliens in state prisons and local jails: Number: 
4,836; 
Offenses for illegal aliens in state prisons and local jails: Percent: 
1%. 

Criminal offense: Kidnapping; 
Total offenses: Number: 3,236; 
Total offenses: Percent: <1%; 
Offenses for illegal aliens in federal prisons: Number: 837; 
Offenses for illegal aliens in federal prisons: Percent: <1%; 
Offenses for illegal aliens in state prisons and local jails: Number: 
2,399; 
Offenses for illegal aliens in state prisons and local jails: Percent: 
1%. 

Criminal offense: Arson; 
Total offenses: Number: 457; 
Total offenses: Percent: <1%; 
Offenses for illegal aliens in federal prisons: Number: 173; 
Offenses for illegal aliens in federal prisons: Percent: <1%; 
Offenses for illegal aliens in state prisons and local jails: Number: 
284; 
Offenses for illegal aliens in state prisons and local jails: Percent: 
<1%. 

Criminal offense: Other; 
Total offenses: Number: 24,310; 
Total offenses: Percent: 4%; 
Offenses for illegal aliens in federal prisons: Number: 9,403; 
Offenses for illegal aliens in federal prisons: Percent: 4%; 
Offenses for illegal aliens in state prisons and local jails: Number: 
14,907; 
Offenses for illegal aliens in state prisons and local jails: Percent: 
4%. 

Total; 
Total offenses: Number: 691,890; 
Total offenses: Percent: 100%; 
Offenses for illegal aliens in federal prisons: Number: 267,709; 
Offenses for illegal aliens in federal prisons: Percent: 100%; 
Offenses for illegal aliens in state prisons and local jails: Number: 
424,181; 
Offenses for illegal aliens in state prisons and local jails: Percent: 
100%. 

[End of table]

Convictions: Federal Prison Illegal Alien Inmates: Almost 90 percent of 
this portion of our study population was convicted of immigration or 
drug offenses: 

Offense: Immigration; 
Number: 12,694; 
Percent: 68%. 

Offense: Drugs; 
Number: 3,978; 
Percent: 21%. 

Offense: Unknown; 
Number: 1,183; 
Percent: 6%. 

Offense: Weapons, explosives, arson; 
Number: 251; 
Percent: 1%. 

Offense: Fraud, bribery, extortion ; 
Number: 185; 
Percent: 1%. 

Offense: Burglary, larceny, property crimes; 
Number: 95; 
Percent: 1%. 

Offense: Assault; 
Number: 41; 
Percent: <1%. 

Offense: Robbery; 
Number: 28; 
Percent: <1%. 

Offense: Kidnapping; 
Number: 26; 
Percent: <1%. 

Offense: Court, corrections; 
Number: 25; 
Percent: <1%. 

Offense: Homicide; 
Number: 13; 
Percent: <1%. 

Offense: Other; 
Number: 62; 
Percent: <1%. 

Offense: Totals; 
Number: 18,581; 
Percent: 100.00%. 

[End of table]

Location of Arrests: Illegal Aliens In Our Study Population: Eighty 
percent of all arrests occurred in three statesCalifornia, Texas, and 
Arizona: 

[See PDF for image]

[End of figure] 

Location of Arrests: Federal Prison Illegal Alien Inmates: Seventy-one 
percent of all arrests occurred in three statesCalifornia, Texas, and 
Arizona: 

[See PDF for image]

[End of figure] 

Location of Arrests: State Prison and Local Jail Illegal Alien Inmates: 
Eighty-seven percent of all arrests occurred in three 
statesCalifornia, Texas, and Arizona: 

[See PDF for image]

[End of figure] 

[End of slide presentation]

[End of section]

Enclosure II: Objectives, Scope, and Methodology:

Using data we had obtained for our report, Information on Criminal 
Aliens Incarcerated in Federal and State Prisons and Local Jails, GAO-
05-337R, we selected our study population of aliens that illegally 
entered the United States using the following methodology. We started 
with data we obtained from the Federal Bureau of Prisons (BOP) on the 
population of aliens incarcerated in federal prison as of December 27, 
2003. We added to this the population of convicted criminal aliens 
incarcerated in state prisons and local jails between July 1, 2002, and 
June 30, 2003 for whom state and local governments sought reimbursement 
under the State Criminal Alien Assistance Program (SCAAP).[Footnote 7] 
These two populations were chosen because they were the latest 
population data we had when we began our analysis. From this combined 
population we identified those criminal aliens that had both an alien 
identification number and an FBI identification number in the data 
records we obtained. An alien identification number is a unique number 
assigned to an alien who has come into contact with immigration 
authorities. The FBI identification number is a unique identifier the 
FBI assigns to a set of fingerprints that allows linking relevant 
records of arrests and any subsequent activity within the criminal 
justice system. We needed to have alien identification numbers in order 
to be able to identify those aliens illegally in the United States and 
FBI numbers in order to obtain the relevant criminal history record 
information from the FBI. For those criminal aliens with both an alien 
identification number and an FBI identification number, we requested 
that the U.S. Immigration and Customs Enforcement (ICE) within the 
Department of Homeland Security identify those aliens that, according 
to their records, had entered the country illegally. For those aliens 
that ICE identified as having entered the country illegally, we 
provided the FBI number and other identifying information to the FBI 
and requested their criminal history records. The criminal history 
record for each unique FBI identification number contained the dates of 
each arrest, the arresting agency, an offense code,[Footnote 8] and a 
literal description of each offense for which the alien was arrested, 
e.g., drug possession, burglary, robbery. The arrest information for 
each illegal alien is all arrests recorded in IAFIS as of October 28, 
2004. Table 1 describes the number of criminal aliens at each level of 
our analysis. 

Table 1: Selection of Illegal Alien Study Population Used For Our 
Analysis:

Number of convicted criminal aliens; 
Inmates incarcerated in federal prison on December 27, 2003: 46,063; 
Inmates incarcerated by state prisons and local jails between July 1, 
2002, and June 30, 2003, and submitted to SCAAP for reimbursement: 
262,105. 

Number of unique convicted criminal aliens with a FBI identification 
number and an alien identification number; 
Inmates incarcerated in federal prison on December 27, 2003: 36,390; 
Inmates incarcerated by state prisons and local jails between July 1, 
2002, and June 30, 2003, and submitted to SCAAP for reimbursement: 
59,427. 

Number of the above unique convicted criminal aliens that ICE 
determined to have entered illegally; 
Inmates incarcerated in federal prison on December 27, 2003: 18,581; 
Inmates incarcerated by state prisons and local jails between July 1, 
2002, and June 30, 2003, and submitted to SCAAP for reimbursement: 
36,741. 

Total population of illegal aliens used in our analysis; 
Inmates incarcerated in federal prison on December 27, 2003: 55,322. 

Source: GAO:

[End of table]

To determine the number of arrests for our study population of illegal 
aliens, we totaled the number of unique dates of arrest for each unique 
FBI number contained in the FBI criminal history records we obtained. 
The earliest arrest record was in 1947, the latest October 28, 2004. 
The criminal history records contained several hundred thousand 
different literal descriptions of arrest offenses. To determine the 
offenses for which these illegal aliens were arrested, we categorized 
the arrest descriptions contained in the criminal history records into 
1 of 19 major offense categories (e.g., immigration, drugs) using FBI 
guidance to law enforcement agencies on how to categorize different 
types of crimes. FBI officials concurred with the way we categorized 
the literal descriptions into the 19 major offense categories. To 
identify the states these illegal aliens were arrested in, we analyzed 
the data contained in the arresting agency field of the criminal 
history record for each unique date of arrest. 

Data Reliability:

We determined that the BOP data are sufficiently reliable for the 
purposes of this report. To assess the reliability of the data, we 
discussed with responsible BOP officials how data on the number of 
federal inmates and whether they are a citizen or an alien are 
collected and maintained in BOP's inmate tracking system called SENTRY. 
We reviewed BOP policies and procedures related to entering data into 
the SENTRY system and reviewed a Department of Justice Inspector 
General review of the SENTRY system. 

We determined that SCAAP data are sufficiently reliable for the 
purposes of this report. To assess the reliability of the SCAAP data, 
we discussed with responsible BJA officials how data on criminal aliens 
reimbursed through SCAAP are collected and maintained. We reviewed BJA 
SCAAP policies and procedures and guidance on how state and local 
jurisdictions can apply for reimbursement under the program. State and 
local jurisdictions submit inmates to BJA for reimbursement based on 
the inmates' self-reporting their country of citizenship or place of 
birth. The state and local jurisdictions certify they have exercised 
due diligence in determining which inmates qualify for reimbursement 
and the inmates' data, such as name and if available, alien 
identification and FBI identification numbers. 

We determined that ICE data are sufficiently reliable for the purposes 
of this report. To assess the reliability of ICE's determination that 
aliens with both an alien identification number and an FBI 
identification number had entered illegally, we discussed with the ICE 
official who conducted the analysis the process he used to make this 
determination. The determination was made after querying several 
immigration databases using the unique alien identification number we 
had supplied. 

We determined that the FBI's IAFIS data on arrests are sufficiently 
reliable for the purposes of this report. To assess the reliability of 
the data, we discussed with responsible FBI officials how data on 
arrests are collected and maintained in IAFIS. We reviewed FBI policies 
and procedures related to entering data into the FBI system. The FBI 
estimates 8 percent of the criminal arrests are no longer maintained by 
the FBI because 7 states, Colorado, Florida, Montana, Oklahoma, Oregon, 
New Jersey, and North Carolina only report their first arrest to the 
FBI. 

We performed our work from October 2004 through May 2005 in accordance 
with generally accepted government auditing standards. 

FOOTNOTES

[1] Estimates of the Unauthorized Immigrant Population Residing in the 
United States: 1990 to 2000, Office of Policy and Planning, U.S. 
Immigration and Naturalization Service. 

[2] Estimates of the Size and Characteristics of the Undocumented 
Population, Jeffrey S. Passel, Pew Hispanic Research Center, March 
2005. 

[3] An alien legally or illegally in the United States who has been 
convicted of a crime. 

[4] GAO, Information on Criminal Aliens Incarcerated in Federal and 
State Prisons and Local Jails, GAO-05-337R (Washington, D.C.: April 7, 
2005). 

[5] IAFIS contains the fingerprints and corresponding criminal history 
for more than 47 million subjects. The fingerprints and corresponding 
criminal history information are submitted voluntarily by federal, 
state and local law enforcement agencies. 

[6] For example, a burglar may enter a home, steal some of the victim's 
property, and drive away in the victim's car. If arrested, the person 
could be charged with three offenses, burglary, theft, and motor 
vehicle theft. 

[7] The Department of Justice Bureau of Justice Assistance (BJA) 
program that reimburses state and local governments for a portion of 
their costs of incarcerating some, but not all, criminal aliens 
illegally in the country. 

[8] A numeric code that the arresting law enforcement agency assigns to 
the criminal offense.