Forensics Unit 2
What is the goal of crime scene investigation? - correct answer-to recognize, document, and
collect evidence at the scene of a crime. Solving a crime will depend on piecing together the
evidence to form a picture of what happened at the crime scene.
What did Dr. Edmund Locard, director of the world's first forensic laboratory in Lyon, France,
strongly believe? - correct answer-that every criminal can be connected to a crime by small
particles carried from the scene.
Locard's Exchange Principle - correct answer-1. whenever 2 objects come in contact with
one another, a cross-transfer of physical evidence can occur.
2. The intensity, duration, and nature of materials in contact determine the extent of the
transfer.
In what 2 ways can evidence can classified? - correct answer-direct evidence and
circumstantial evidence
direct evidence - correct answer-firsthand observations (eyewitness account, videos,
confessions)
circumstantial evidence - correct answer-indirect evidence that can be used to imply a fact
but does not directly prove it. Example: finding a suspect's gun at a crime scene is
circumstantial evidence that the suspect was there.
Types of circumstantial evidence: - correct answer-- physical evidence
- biological evidence
- trace evidence
physical evidence - correct answer-synthetic fibers, weapons, bullets, shell casings, paint
chips, documents, imprints and prints (shoes, tires, etc.), toolmarks, soil, drugs, etc.
biological evidence - correct answer-body or body parts, body fluids, hair, leaves or other
plant parts, natural fibers, feathers, wood
trace evidence - correct answer-small but measurable amounts of physical or biological
material found at a crime scene
Examples: strand of hair, fingerprint, DNA, drop of blood, pollen, gunshot residue
The more circumstantial evidence there is... - correct answer-the greater weight it carries
(probability and statistics)
class evidence - correct answer-narrows evidence to a group of persons or things
Example: blood type - can be A, B, AB, O. Finding one type at a crime scene narrows down
the suspects to a smaller group
, individual evidence - correct answer-narrows evidence down to a single person or thing
Example: fingerprints, handwriting, DNA, and sometimes physical matches
Importance of Evidence - correct answer-- can prove a crime has been committed and set
the scene for the investigation (example: Gasoline at the scene of a fire may prove arson)
- can back up witness testimony or prove it false
- can link a suspect with a victim or with a crime scene
- can determine the identity of people associated with a crime
- allows investigators to reconstruct a crime (example: blood spatter may show here suspect
and victim were in relation to one another and indicate what happened in what order)
The crime scene investigation team - correct answer-a group of professional investigators,
each trained in a variety of special disciplines
Who makes up the crime scene investigation team? - correct answer-- first Police Officer on
the scene
- backup Police and possible a district attorney (elected or appointed official who represents
the gov. in the prosecution of criminal offenses)
- medics (if necessary)
- Investigator/Detective(s)
- medical examiner (if necessary)
- photographer and/or Field Evidence Technician
- lab experts
Why must everyone on the crime scene investigation team wear protective gear? - correct
answer-to prevent contamination of crime scene
The Seven S's of Crime Scene Investigation - correct answer-- securing the scene
- separating the witnesses
- scan the scene
- see the scene
- sketching the scene
- search for evidence
- securing and collecting evidence
securing the scene - correct answer-the first responding police officer must make sure the
scene is secure by first making sure all individuals in the area are safe and second by
preserving evidence
He or she should:
- obtain medical assistance if needed
- arrest suspects
- isolate the area
- request additional needs for investigations (more officers, experts, etc.)
What is the goal of crime scene investigation? - correct answer-to recognize, document, and
collect evidence at the scene of a crime. Solving a crime will depend on piecing together the
evidence to form a picture of what happened at the crime scene.
What did Dr. Edmund Locard, director of the world's first forensic laboratory in Lyon, France,
strongly believe? - correct answer-that every criminal can be connected to a crime by small
particles carried from the scene.
Locard's Exchange Principle - correct answer-1. whenever 2 objects come in contact with
one another, a cross-transfer of physical evidence can occur.
2. The intensity, duration, and nature of materials in contact determine the extent of the
transfer.
In what 2 ways can evidence can classified? - correct answer-direct evidence and
circumstantial evidence
direct evidence - correct answer-firsthand observations (eyewitness account, videos,
confessions)
circumstantial evidence - correct answer-indirect evidence that can be used to imply a fact
but does not directly prove it. Example: finding a suspect's gun at a crime scene is
circumstantial evidence that the suspect was there.
Types of circumstantial evidence: - correct answer-- physical evidence
- biological evidence
- trace evidence
physical evidence - correct answer-synthetic fibers, weapons, bullets, shell casings, paint
chips, documents, imprints and prints (shoes, tires, etc.), toolmarks, soil, drugs, etc.
biological evidence - correct answer-body or body parts, body fluids, hair, leaves or other
plant parts, natural fibers, feathers, wood
trace evidence - correct answer-small but measurable amounts of physical or biological
material found at a crime scene
Examples: strand of hair, fingerprint, DNA, drop of blood, pollen, gunshot residue
The more circumstantial evidence there is... - correct answer-the greater weight it carries
(probability and statistics)
class evidence - correct answer-narrows evidence to a group of persons or things
Example: blood type - can be A, B, AB, O. Finding one type at a crime scene narrows down
the suspects to a smaller group
, individual evidence - correct answer-narrows evidence down to a single person or thing
Example: fingerprints, handwriting, DNA, and sometimes physical matches
Importance of Evidence - correct answer-- can prove a crime has been committed and set
the scene for the investigation (example: Gasoline at the scene of a fire may prove arson)
- can back up witness testimony or prove it false
- can link a suspect with a victim or with a crime scene
- can determine the identity of people associated with a crime
- allows investigators to reconstruct a crime (example: blood spatter may show here suspect
and victim were in relation to one another and indicate what happened in what order)
The crime scene investigation team - correct answer-a group of professional investigators,
each trained in a variety of special disciplines
Who makes up the crime scene investigation team? - correct answer-- first Police Officer on
the scene
- backup Police and possible a district attorney (elected or appointed official who represents
the gov. in the prosecution of criminal offenses)
- medics (if necessary)
- Investigator/Detective(s)
- medical examiner (if necessary)
- photographer and/or Field Evidence Technician
- lab experts
Why must everyone on the crime scene investigation team wear protective gear? - correct
answer-to prevent contamination of crime scene
The Seven S's of Crime Scene Investigation - correct answer-- securing the scene
- separating the witnesses
- scan the scene
- see the scene
- sketching the scene
- search for evidence
- securing and collecting evidence
securing the scene - correct answer-the first responding police officer must make sure the
scene is secure by first making sure all individuals in the area are safe and second by
preserving evidence
He or she should:
- obtain medical assistance if needed
- arrest suspects
- isolate the area
- request additional needs for investigations (more officers, experts, etc.)
