Lecture 6: CSI and Evidence Collection Flashcards
What is the purpose of crime scene investigation?
To recognize, document and collect evidence at a crime scene.
Solving the crime depends on piecing together the evidence.
What principle states that a cross transfer of physical evidence can occur when a person comes into contact with an object?
Locard’s Principle (Principle of Exchange)
This principle explains that materials in contact determine the extent of transfer.
What are the two main types of evidence?
- Direct: Firsthand observations
- Circumstantial: Indirect evidence, including physical and biological
What is the difference between class evidence and individual evidence?
- Class evidence: narrows identity to a group (e.g., blood type)
- Individual evidence: identifies a single person (e.g., DNA)
What are some examples of trace evidence?
- Hair on brush
- Fingerprints on glass
- Soil tracked inside on shoes
- Drop of blood on t-shirt
- A used facial tissue
- Paint chips
- Broken glass
- Fiber from clothing
Trace evidence can be microscopic or small items found at a crime scene.
Who are the personnel involved in crime scene investigation?
- Police Officers: first line
- Crime Scene Investigators: document crime, collect physical evidence
- Medical Examiners: coroners to determine cause of death
- Detectives: look for leads, interview witnesses, communicate with CSI
What is the first step in the procedure of crime scene investigation?
Securing and isolating the scene
This is crucial to preserve evidence.
What are the first procedures in CSI?
- Securing and isolating the scene
- Recording the scene (scanning, seeing, sketching)
- Searching for evidence
- Securing and collecting evidence
What is involved with securing and isolating the SOC?
- Only investigative personnel assigned to the scene should be admitted
- Log of who enters and exits at what time
What should crime scene notes include?
- WHO: The person who contacted the investigator
- WHO: Personnel in and out of scene
- WHEN: Time of contact
- WHAT: Preliminary information disclosed
- WHERE: Location and description of evidence
- Interview of the first responding officer
What is the purpose of crime scene photography?
To show
- Layout of scene
- Position of evidence to be collected
- Relation of objects
What are the two types of sketches used in crime scene investigation?
- Rough sketch
- Accurate dimensions
- Location of all objects
- Compass heading north
- Items labeled with no./letters
- Finished sketch
- Aesthetics
- Includes info on rough sketch
- Computer-aided drafting
What are the five common search patterns in a crime scene?
- Spiral
- Strip or line
- Grid
- Quadrant/zone
- Wheel or ray
Each pattern is used based on the scene’s characteristics.
What is a Standard/Reference Sample?
Physical evidence whose origin is known, such as blood or hair from a suspect.
It can be compared to evidence found at the crime scene.
What does crime scene reconstruction involve?
Forming a hypothesis of the sequence of events.
True or False: Staging a crime scene can involve making it look like a suicide to cover a murder.
True
Staging is a tactic used to mislead investigations.
What is staging in the context of crime scenes?
Staging is when someone who’s committed a crime attempts to make the scene look like something that it isn’t.
What is a common example of staging a crime scene?
Staging a suicide to cover a murder.
What might indicate that a crime scene was staged?
Evidence does not match testimony.
Fill in the blank: A person committing insurance fraud stages a breaking and entering by ensuring that _______ is missing.
[jewelry]
What type of crime might a murderer commit to stage a scene?
Breaking a window or prying a lock.
What is one motive for staging a fire at a crime scene?
To cover up another crime.
What principle states that every contact leaves a trace?
Locard’s principle.
What must be maintained to ensure evidence is valid in an investigation?
- Chain of Custody=List of all people who came into possession of an item of evidence
What are the steps involved in crime scene investigation?
- Proper handling
- Collection
- Labeling of evidence
Who analyzes the evidence collected from a crime scene?
Forensic lab.
How to determine if a crime scene was staged?
- If wound on victim matches weapon employed
- Mood and actions of victim before the event
- Mood and actions of suspect before the event
What case is mentioned as an example of a potential staged crime scene?
The hanging death of Sheena Morris.
What is a common motive for staging a fire?
To destroy evidence of the underlying crime.
What should be done with physical evidence after it is collected?
- Packed in containers
- Air-dried and placed individually
- E.g. Manila envelopes, screw-cap vials, sealable plastic bags
What is the significance of analyzing evidence in a forensic lab?
Results are provided to detectives to fit into the crime scenario.
Summarize the steps that should be done in CSI
- Obtain medical assistance for individuals
- Arrest perpetrator
- Secure crime scene, establish crime-scene perimeter
- Record crime scene
- Conduct systematic search for evidence
- Locate physical evidence
- Collection physical evidence
- Analyze evidence
