LECTURE 4: CSI // CHAPTER 2 Flashcards
What is a Crime Scene?
- Anywhere that evidence may be located that will help explain the events that occurred
Property
People – victim/ offender/ could be material on them
Space
Vehicles
Define the variable nature of a crime scene & why CSI is important
- every scene is different
- no set rulebook for how to investigate
(the only consistency in crime scene investigation is inconsistency) - it is the first part of the process that leads to conviction or exoneration
- if not done correctly from the beginning it lays a bad foundation for the rest of the investigation
- what happens at the scene effects everything thereafter
Define the objectives of CSI
- to determine if a crime has been committed (if there is no conceivable offence there is no crime scene)
- to discover and document all relevant facts
- to identify and eliminate suspects as a result of collected physical and testimonial evidence
- to locate and apprehend offender
- to maintain a proper CoC
- to testify as a witness to the collected evidence
Define and discuss the role, value and utility of physical evidence
- Can prove the crime has been committed or establish key elements of the crime
- It can establish the ID of persons associated with the crime
- It can place the suspect in contact with the victim or with the crime scene
- It can exonerate the innocent
- It can corroborate the victims testimony
- A suspect confronted with physical evidence is more likely to make admissions/confess
- Court has become reliant on it
- Juries expect it- the absence of evidence is not evidence of absence
- Negative evidence (no physical evidence where expected) may provide useful information (false reports)
List the ways in which evidence may be preserved and how chain of custody is
maintained
Collection and preservation of evidence
- evidence should be handled as little as possible
- items packaged individually
- known/ control samples needed for comparative analysis
- paper is preferred packaging
- sealable airtight containers for chemical evidence and accelerants
- avoid contamination
Chain of custody (CoC)
- court requires proof that evidence collected from scene and submitted to court are the same
- who had contact with evidence
- when they were in contact
- what were the circumstances of them having it
- what changes were made to it
Datum:
a fixed reference pointbject
Artifact:
human-made or modified portable object
Feature:
non-portable artifact, fire pit, house, garden
Organic/ environmental remains:
natural remnants that nonetheless indicate human activity, animal bones, plants
Provenance:
origin or derivation of an item in 3-dimensional space
Task of first officer
- Secure the scene and prevent destruction or alteration of the critical and sometimes fragile context of a crime scene
1. Detain any potential suspects
2. Render medical assistance to those in need
3. Do not destroy, alter, or add any evidence at the scene
4. Prevent others, even superior, from doing the same
Chain of custody
- Most important piece of paper generated at a crime scene
- Documents the movements of evidence from the time it Is obtained to the time it is presented in court
nitrile gloves
provide protection from acids, alkaline solutions, hydraulic fluid photographic solutions, fuels, aromatics and some solvents - also cut resistant
neoprene gloves
offer protection from acids, solvents alkalies, bases, and most refrigerants
latex or natural rubber gloves
are resistant to mild acids, caustic materials, genocides - will degrade if exposed to gasoline, kerosene and prolonged exposure to excessive heat or direct sunlight
