Mission-Specific Competencies:

Evidence Preservation and Sampling

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Objectives (1 of 3)

• Understand the role that all first responders have in preserving evidence

• Identify when a hazardous material/WMD incident could be a violation of criminal law

• Identify the law enforcement agencies that could be involved in an investigation

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Objectives (2 of 3)

• Describe the various types of evidence including physical and trace evidence

• Understand the difference between evidence preservation and sampling

• Describe the chain-of-custody and its importance

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Objectives (3 of 3)

• Understand how witnesses are identified

• Describe the key concepts to be taken into consideration when analyzing, planning, and implementing an evidence preservation and sampling response

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Evidence (1 of 2)

• Information gathered to help determine cause of incident

• Forensic evidence is used in legal process

• Strict procedures must be followed

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Evidence (2 of 2)

• Important for identifying person(s) responsible for event

• Evidence preservation should never impede:– Fire suppression– Life-saving operations

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General Indicators That a Crime Is Involved

• Anonymous threats before incident

• Nearby notes or graffiti claiming responsibility

• Suspicious activity on scene

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Letters and Packages (1 of 2)

• May hold explosive or hazardous materials

• Causes for suspicion:– Excessive postage (to ensure package is not

returned to sender)– Threatening messages on package– Leaks or stains

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Letters and Packages (2 of 2)

It is important to check suspicious packages for visible leaks or stains.

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Illicit Laboratories (1 of 2)

• Produce methamphetamine and other drugs

• Construct explosive devices

• Manufacture chemical agents

• Culture biological agents

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Illicit Laboratories (2 of 2)

• Causes for suspicion:– Fences– Excessive window coverings– Enhanced ventilation/filtration systems– Chemical storage cylinders– Lab equipment

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Environmental Crimes (1 of 3)

• Intentional release or disposal of hazardous materials– Air– Ground– Water systems

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Environmental Crimes (2 of 3)

• Causes for suspicion:– Containers discarded at site– Staining or odors near street drainage

systems– Dead or dying plants, insects, animals nearby

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Environmental Crimes (3 of 3)

Crop-dusting equipment can be used as a means to commit environmental crimes.

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If No Crime Was Committed

• Evidence collection is still important

• Basis for lawsuits victims may file

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Investigative Jurisdictions (1 of 2)

• Criminal investigations start with Authority Having Jurisdiction (AHJ)

• It determines who has investigative authority

• Multiagency task forces may be formed

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Investigative Jurisdictions (2 of 2)

• Agencies that may be involved:– Postal Inspection Service– Drug Enforcement Administration– Federal Bureau of Investigation– Environmental Protection Agency

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Types of Evidence

• Physical evidence

• Trace (transfer) evidence

• Demonstrative evidence

• Direct evidence

• Circumstantial evidence

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Physical Evidence (1 of 2)

• Observed

• Photographed

• Measured

• Collected

• Examined in a laboratory

• Presented in court

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Physical Evidence (2 of 2)

Physical evidence can be observed.

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Trace (Transfer) Evidence (1 of 2)

• Minute quantity of physical evidence

• Conveyed from one place to another

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Trace (Transfer) Evidence (2 of 2)

A side-by-side comparison of the color and texture of soil can eliminate a large percentage of samples as not being matches.

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Demonstrative Evidence (1 of 2)

• Used to validate a theory

• To show how something could have occurred

• Example: Cast of tool mark found at scene

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Demonstrative Evidence (2 of 2)

A cast of a tool mark.

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Direct Evidence (1 of 2)

• Facts observed or reported firsthand

• Statements

• Videotape

• Can include physical evidence

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Direct Evidence (2 of 2)

A videotape of a person committing a crime is considered to be direct evidence.

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Circumstantial Evidence

• Based on facts observed firsthand

• Can be used to prove a theory

• Common at fire scenes

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Evidence Preservation

• Process of protecting potential evidence

• Until it can be documented, sampled, collected

• Responders should leave it in place

• Move no more debris than necessary

• Cover to protect if necessary

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Contamination

• Evidence should not be contaminated

• Use new tools to collect each piece of evidence

• Investigators use special containers to store evidence

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Chain of Custody (1 of 3)

• Other terms– Chain of evidence– Chain of possession

• Continuous possession and control of evidence

• From discovery until presented in court

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Chain of Custody (2 of 3)

• Every transfer of possession must be documented

• Leave evidence where you find it

• Report to a senior official

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Chain of Custody (3 of 3)

Evidence should remain where you find it until you can turn it over to an officer or investigator.

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Identifying Witnesses

• Interviews conducted by:– Incident investigator– Law enforcement officer

• If neither is present:– Get witness’s name, address, phone number– Give to investigator

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Rumors and Reporters

• State opinions on probable cause only to investigator– Rumors circulate easily

• Statements to reporters are made by official spokesperson– After investigator and IC agree on accuracy

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12 Steps of Evidence Sampling

(1 of 2)

1. Preparation

2. Approach the scene

3. Secure and protect the scene

4. Initiate a preliminary survey

5. Evaluate physical evidence possibilities

6. Prepare a narrative description

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12 Steps of Evidence Sampling

(2 of 2)

7. Describe the scene photographically

8. Prepare a diagram or sketch of the scene

9. Conduct a detailed search

10. Record and collect physical evidence

11. Conduct the final survey

12. Release the scene

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Sampling Team

• Consists of three people– Sampler– Assistant– Documenter

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Securing, Characterizing, and Preserving the Scene

• Necessary as soon as incident identified as criminal

• Limit access

• Early characterization of the scene

• Preserve evidence

• Notify law enforcement agency

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Document Personnel and Scene Activity

• Document identity/purpose of personnel– Present when you arrive– Who enter after crime scene is so

characterized

• “Tag in/tag out” records work

• Record initial on-scene observations

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Notification

• Explosive ordnance disposal (EOD) personnel

• Law enforcement agency having jurisdiction

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Identifying Samples to Be Collected

• Indicate where evidence is located

• Colored cones or tape

• Nondestructive markings or identification

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Collecting Samples

• Collecting all potential evidence may be too much

• Use various sampling techniques

• Nondestructive field screening methods

• Prevent secondary contamination

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Documentation of Evidence

• Document sampling/collection process– Photographs– Videotape

• Note name of person sampling

• Note location, time sample was collected

• Note physical state, quantity, container

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Sampling and Field Screening Protocol

• Plan must be followed

• Ensure that evidence is safe before it enters laboratory

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Labeling, Packaging, and Decontamination

• Place in appropriate container

• Label as to type of hazard

• Perform technical decontamination

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Summary (1 of 2)

• Responders need to consider calls they respond to might be the result of criminal activities

• Local law enforcement must be notified• Preserve, sample, and collect evidence so

that it can be used in prosecution

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• Types of evidence are physical, trace, demonstrative, direct, and circumstantial evidence

• Sampling, preservation, and documentation must be given due attention

Summary (2 of 2)

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