Technical Working Group on Biological 

Evidence Preservation

Project Briefing

American Academy of Forensic Science (AAFS) 

Annual Meeting

Thursday, February 20, 2014
The State of Biological Evidence Preservation 

“In order for qualified forensic science experts 

to testify competently about forensic 

evidence, they must first find the evidence in 

a usable state and properly preserve it.”

- NAS Report
What does your evidence room look like?
“Bad” Evidence Rooms
“Bad” Evidence Rooms
“Good” Evidence Rooms
“Good” Evidence Rooms
Group Charge

To create best practices and guidance 

to ensure the integrity, prevent the loss, 

and reduce the premature destruction 

of biological evidence --

after collection through post-conviction 

proceedings.
TWG Members

Sue Ballou, Program Manager, Forensics 

Program, NIST

Phylis Bamberger Retired Judge, 

Taskforce for Wrongful Convictions, 

New York State Bar Association

Rebecca Brown, Police Advocate, 

Innocence Project

Larry Brown, Property Manager, Los 

Gatos/Monte Sereno PD

Dennis Davenport, Senior Crime Scene 

Investigator, Commerce City PD

Rock Harmon, Consultant, DNARock

Cynthia Jones, Associate Professor of 

Law, American University

Ralph Keaton, Executive Director, 

ASCLD/LAB

William Kiley, IAPE

Margarent Kline, Research Biologist, 

NIST

Karen Lanning, Unit Chief, Evidence 

Control Unit, FBI

Gerry Laporte, Program Manager, 

Office of Investigative and Forensic 

Sciences, NIJ

Joe Latta, Exec. Director, IAPE

Linda Ledray, Director, Resource 

Center, SANE-SART

Randy Nagy, VP Sales and Marketing, 

Bode Technology

Brian Ostrom, Criminalist, Portland 

Metro Forensic Laboratory

Yvette Sanchez-Owens, Commanding 

Officer, Scientific Investigation 

Division, LAPD

Lisa Schwind, Unit Head, Forensic 

Service and Education, Office of the 

Public Defender, State of Delaware

Stephanie Stoiloff, Commander, 

Forensic Services Bureau, MiamiDade Police Department

Shannan Williams, Associate, Forensics 

Program, NIST/OLES
Group Outputs

1. The Biological Evidence Preservation Handbook: Best 

Practices for Evidence Handlers (published in April 2013)

2. TWG Website: 

http://www.nist.gov/oles/forensics/bioev.cfm

3. Biological Evidence Preservation: Considerations for 

Policy Makers (To be released in Spring 2014)

4. RFID Technology in Forensic Evidence Management: 

Assessment of Barriers, Benefits, and Costs to 

Implementation (To be released in Spring 2014)
The Biological Evidence Preservation 

Handbook: Best Practices for Evidence 

Handlers

Published April 2013

Available at: 

http://www.nist.gov/oles/

forensics/bioev.cfm
I-1: All persons who have responsibility for the intake and/or 

storage and disposition of biological evidence should take 

online, in-classroom, or other forms of training on evidence 

management. 

I-2: Prior to a property and evidence custodian accepting 

biological evidence, it should be clearly marked and labeled 

by the submitter as biological evidence, allowing it to be 

tracked within the evidence management system and stored 

appropriately from intake through disposition. 

Retaining Biological Evidence – Key 

Recommendations
Retaining Biological Evidence – Key 

Recommendations

CRIME CATEGORY/CASE STATUS/PERIOD OF RETENTION CHART

In the exercise of his/her duties, the property and evidence custodian may determine the status of cases

in his/her custody and may decide whether contact should be made with the investigating officer or

prosecutor. Crime categories/classifications vary from state to state; therefore, knowledge of the specific

categories in one’s own state is crucial. Table 1-2 provides guidance.

Table I-2: Summary of Biological Evidence Retention Guidelines for Crime Categories

CASE STATUS

Crime

Categories

(NIBRS*)

Open† Charges Filed Adjudicated

Unfounded/

Refused/Denied/

No Further

Investigation

Homicide

Offenses

Retain

indefinitely

Retain

indefinitely

At a minimum,

retain for the

length of

incarceration‡

Dispose of upon

receipt of

authorization§

Sexual Offenses

At a minimum,

retain for the

length of the

statute of

limitations

§

Retain pending

adjudication§

At minimum,

retain for the

length of

incarceration‡

Dispose of upon

receipt of

authorization§

Assault Offenses,

Kidnapping/

Abduction,

Robbery

All Other Group

A & B Offenses

Dispose of upon

receipt of

authorization§

 

* The Federal Bureau of Investigation’s National Incident-Based Reporting System (NIBRS) classifies 22 types of

offenses as Group “A” crimes and 11 types of lesser offenses as Group “B” crimes. Table 1-2 uses the NIBRS

crime categories.

† Cases in which someone was found not guilty after criminal proceedings and additional suspects have not yet

been identified or charged should follow the same guidance as open cases.

‡

Statutes regarding the disposition of biological evidence from homicide, sexual offenses, and other crime

categories vary from state to state. Almost all states that have statutes require that such evidence be held for the

period of incarceration; a few states require that the evidence be held for the period of probation, parole, or

registration as a sex offender. Custodians should check their state statutes. Written authorization for disposal

should be obtained from the assigned case investigator. (Note: If the assigned investigator is no longer employed

by the agency, a designated investigator should give written approval.)

§

Section V provides further guidance regarding the disposition process.

After it is determined that charges will not be sought or filed, evidence, including any biological

evidence, need not be retained unless destruction is prohibited by statute.
I-3: Property and evidence custodians should consult with 

investigators, laboratory analysts, and, when appropriate, 

prosecutors to determine whether only representative 

sample(s) should be retained in situations in which samples 

are too large or too costly to store. Property and evidence 

custodians, investigators, laboratory analysts, and 

prosecutors should discuss situations in which prosecutors 

should be consulted. These decisions should not be made 

exclusively by property and evidence custodians. 

BULKY EVIDENCE: CONSIDERATIONS FOR LONG-TERM EVIDENCE RETENTION

To facilitate forensic testing for trial and post-conviction proceedings, it is essential to store and track as

much of the evidence as necessary. However, it may be extremely difficult to maintain large or bulky

items of evidence from which biological material is derived. Figure I-1 depicts the collection of biological

material from a large bulky item—such as a couch—for forensic testing. For the long term, agencies

might find it sufficient to retain samples taken from a large item (see B. and C. in figure I-I) as opposed

to the large item on which biological evidence may have been located (see A. in figure I-I). Other

examples of bulky evidence include a car, the wall/ceiling of a house, carpet, or another large piece of

furniture such as a bed. If the origin of a sample is well documented (such as through photographs or

case files), it may not be necessary to store the entire couch for testing and future re-testing.

Figure I-1: Collection of evidence from large/bulky items.

Retaining Biological Evidence – Key 

Recommendations
III-1: In tandem with state or local legislatures, managers in 

law enforcement and relevant stakeholders should advocate 

for additional resources and funding to ensure the integrity 

of biological evidence through prioritizing the packaging, 

storage, maintenance, and security of the evidence in their 

jurisdictions.

III-3: Each law enforcement agency should develop a 

protocol for standardizing evidence packaging materials and 

customizing shelving to allow for more efficient retrieval of 

evidence stored in property rooms. 

III-5: Each law enforcement agency should have a policy 

and procedure for the storage of biological evidence. 

Packaging and Storing Biological Evidence –

Key Recommendations
Short-Term Storage Conditions

http://www.nist.gov/oles/forensics/upload/Works-Citeddoc-BioEvidence-Handbook.pdf 
Long-Term Storage Conditions

http://www.nist.gov/oles/forensics/upload/Works-Citeddoc-BioEvidence-Handbook.pdf 
TWG did not to recommend that all biological evidence be frozen 

for the following reasons: 

1.Scientific research and current trends in DNA analysis. Studies have 

demonstrated the highly stable nature of DNA and technology has become 

more sensitive, enabling analyses of smaller amounts of DNA. 

2.Evidence is often held in multiple locations throughout it’s 

lifecycle. This makes it extremely difficult to maintain the evidence in a 

constant frozen state and scientific evidence shows that thawing and refreezing biological evidence degrades the DNA and hinders analysis. 

3. Lengthy retention times required by legislation make freezing all 

biological evidence types extremely costly. Given the marginal benefits 

and potentially destructive nature of freezing and thawing cycles, the cost 

of freezing for indefinite periods of time may be an unnecessary expense 

for resource strapped jurisdictions. 

To Freeze or Not to Freeze Biological Evidence
IV-3: Yearly inventories should be conducted to verify that 

the evidence in the property room is present and in its 

specified location. 

IV-5: Each agency must develop an identification system so 

that each item of evidence has a unique identifier. Evidence 

items created from analysis or separated from the original 

evidence item should be documented to show the linkage 

between it and its parent. 

IV-11: Jurisdictions should work to assess and improve 

communications regarding forensic evidence by developing 

consistent procedures and packaging guidelines and by 

integrating evidence-tracking systems across locations. 

Tracking and Chain of Custody – Key 

Recommendations
V-1: Case status reviews should be conducted at least once 

a year to determine eligibility for disposition of evidence 

containing biological evidence. 

V-2: Each agency should designate those authorized to sign 

off on the disposition of biological evidence within a 

jurisdiction. 

V-4: An evidence disposition process should be part of each 

agency’s policy and procedures. 

Biological Evidence Disposition – Key 

Recommendations
Biological Evidence Disposition – Key 

Recommendations
Group Outputs

1. The Biological Evidence Preservation Handbook: Best 

Practices for Evidence Handlers (published in April 2013)

2. TWG Website: 

http://www.nist.gov/oles/forensics/bioev.cfm 

3. Biological Evidence Preservation: Considerations for 

Policy Makers (To be released in Spring 2014)

4. RFID Technology in Forensic Evidence Management: 

Assessment of Barriers, Benefits, and Costs to 

Implementation (To be released in Spring 2014)
Group Outputs

1. The Biological Evidence Preservation Handbook: Best 

Practices for Evidence Handlers (published in April 2013)

2. TWG Website: 

http://www.nist.gov/oles/forensics/bioev.cfm 

3. Biological Evidence Preservation: Considerations for 

Policy Makers (To be released in Spring 2014)

4. RFID Technology in Forensic Evidence Management: 

Assessment of Barriers, Benefits, and Costs to 

Implementation (To be released in Spring 2014)
Biological Evidence Preservation: 

Considerations for Policy Makers

Purpose of Providing Legislative Guidance

• Law compels compliance more than guidelines/best 

practices alone

• Statutory requirements elevates the importance of proper 

handling among various holders of evidence

• Legislation addresses consequences for denial of access

Audience 

• Policy makers, law enforcement management, property 

and evidence management

Release Date

• Spring 2014
Biological Evidence Preservation: 

Considerations for Policy Makers

Topics Covered

• State Taskforces/Commissions

• Biological Evidence Definition

• Retention Guidelines: Crime Categories and Automatic 

vs. Qualified

• Management

• Early Disposition

• Ramifications for Denial of Access

*Guidance is informed by in depth analysis of current 

legislation in 43 states and the District of Columbia
Group Outputs

1. The Biological Evidence Preservation Handbook: Best 

Practices for Evidence Handlers (published in April 2013)

2. TWG Website: 

http://www.nist.gov/oles/forensics/bioev.cfm 

3. Biological Evidence Preservation: Considerations for 

Policy Makers (To be released in Spring 2014)

4. RFID Technology in Forensic Evidence Management: 

Assessment of Barriers, Benefits, and Costs to 

Implementation (To be released in Spring 2014)
Automated Identification Technology (AIT) in 

Forensic Evidence Management

Report Release Date: Spring 2014
Questions?

Stephanie Stoiloff

sstoiloff@mdpd.com

305-471-3037 (office)

786-256-1205 (cell)