2. 10
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
3. 10
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
4. 10
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
5. 10
Evidence (1 of 2)
• Information gathered to help determine
cause of incident
• Forensic evidence is used in legal process
• Strict procedures must be followed
6. 10
Evidence (2 of 2)
• Important for identifying person(s)
responsible for event
• Evidence preservation should never
impede:
– Fire suppression
– Life-saving operations
7. 10
General Indicators That a Crime Is
Involved
• Anonymous threats before incident
• Nearby notes or graffiti claiming
responsibility
• Suspicious activity on scene
8. 10
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
9. 10
Letters and Packages (2 of 2)
It is important to check suspicious packages for visible
leaks or stains.
10. 10
Illicit Laboratories (1 of 2)
• Produce methamphetamine and other
drugs
• Construct explosive devices
• Manufacture chemical agents
• Culture biological agents
11. 10
Illicit Laboratories (2 of 2)
• Causes for suspicion:
– Fences
– Excessive window coverings
– Enhanced ventilation/filtration systems
– Chemical storage cylinders
– Lab equipment
12. 10
Environmental Crimes (1 of 3)
• Intentional release or disposal of
hazardous materials
– Air
– Ground
– Water systems
13. 10
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
14. 10
Environmental Crimes (3 of 3)
Crop-dusting equipment can be used as a means to
commit environmental crimes.
15. 10
If No Crime Was Committed
• Evidence collection is still important
• Basis for lawsuits victims may file
16. 10
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
17. 10
Investigative Jurisdictions (2 of 2)
• Agencies that may be involved:
– Postal Inspection Service
– Drug Enforcement Administration
– Federal Bureau of Investigation
– Environmental Protection Agency
21. 10
Trace (Transfer) Evidence (1 of 2)
• Minute quantity of physical evidence
• Conveyed from one place to another
22. 10
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.
23. 10
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
25. 10
Direct Evidence (1 of 2)
• Facts observed or reported firsthand
• Statements
• Videotape
• Can include physical evidence
26. 10
Direct Evidence (2 of 2)
A videotape of a person committing a crime is considered to
be direct evidence.
27. 10
Circumstantial Evidence
• Based on facts observed firsthand
• Can be used to prove a theory
• Common at fire scenes
28. 10
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
29. 10
Contamination
• Evidence should not be contaminated
• Use new tools to collect each piece of
evidence
• Investigators use special containers to
store evidence
30. 10
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
31. 10
Chain of Custody (2 of 3)
• Every transfer of possession must be
documented
• Leave evidence where you find it
• Report to a senior official
32. 10
Chain of Custody (3 of 3)
Evidence should remain where you find it until you can turn it
over to an officer or investigator.
33. 10
Identifying Witnesses
• Interviews conducted by:
– Incident investigator
– Law enforcement officer
• If neither is present:
– Get witness’s name, address, phone number
– Give to investigator
34. 10
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
35. 10
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
36. 10
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
37. 10
Sampling Team
• Consists of three people
– Sampler
– Assistant
– Documenter
38. 10
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
39. 10
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
40. 10
Notification
• Explosive ordnance disposal (EOD)
personnel
• Law enforcement agency having
jurisdiction
41. 10
Identifying Samples to Be Collected
• Indicate where evidence is located
• Colored cones or tape
• Nondestructive markings or identification
42. 10
Collecting Samples
• Collecting all potential evidence may be
too much
• Use various sampling techniques
• Nondestructive field screening methods
• Prevent secondary contamination
43. 10
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
44. 10
Sampling and Field Screening
Protocol
• Plan must be followed
• Ensure that evidence is safe before it
enters laboratory
45. 10
Labeling, Packaging, and
Decontamination
• Place in appropriate container
• Label as to type of hazard
• Perform technical decontamination
46. 10
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
47. 10
Summary (2 of 2)
• Types of evidence are physical, trace,
demonstrative, direct, and circumstantial
evidence
• Sampling, preservation, and
documentation must be given due
attention
Editor's Notes
Image: Photographed by Glen E. Ellman.
Image: Courtesy of Tim McCabe/USDA
Image: Courtesy of Unified Investigations & Sciences, Inc.
Image: Courtesy of Sirchie Finger Print Labs, Inc.
