Forensics Unit 2 Flashcards
What is the goal of ? CSI
To recognise, document, and collect evidence at a crime scene as well as piece together evidence to form a picture of what happened at a crime scene
Direct Evidence
Statement made under oath/testimonial evidence
Individual Evidence
Narrows an identity to a single person or thing. This is found by either a unique combination of characteristics that could only belong to a person or thing
Always involves a comparison
Circumstantial Evidence
Any object or material relevant to a crime
1. physical evidence,
2. Locard’s exchange principle
3. class vs individual evidence
Class evidence
Narrows an identity to a group of persons or things
Trace Evidence
SMall but measurable amounts of physical or biological material found at a crime scene
Example of Trace Evidence
blood, prints, fibers, hair, body fluids
Who is at a crime scene
Police/district attorney
CSI
Medical examiners
detectives
specialists
Seven S’s of crime scenes
- Secure the scene
- Separate the witnesses
- Scan the Scene
- See to it that crime scene examiners receive overall and close up photos with an without measuring rulers
- Sketch the scene
- Search for evidence
- Secure the collected evidence
Secure the scene
Responsibility: First responder
1st priority: Safety of individuals
2nd priority: Preserving evidence
they establish a perimeter and keep track of people at the scene
Separating the Witnesses
Investigators compared witness notes
What is each witness asked
When did the crime occur
Who called in the scene
Who was the victim
Can the perpetrador be identified
What did you see happen
Where were you when you observed the crime scene
Scan the Scene
Done by forensic examiners
Determines where photos should be taken
Seeing the Scene
Crime scene examiners need to see the scene
they take tons of photos from wide to tight
Sketch the Scene
Accurate rough sketch
Note positions of body/evidence
Objects should be measured from two immovable points
North is labeled
A more accurate sketch is made for court
Searching for Evidence
A spiral, grid, linear, pattern should be walked and location of evidence marked, photographed and sketched
Also oblique lighting needed
Securing and Collecting Evidence
All evidence needs to be properly packaged, sealed, and labeled
How should evidence be stored
Liquids and arson remains in an airtight container
Biological evidence in a breathable contrainters to dry out
Other evidence should be put in a paper bindle then in a bag/container
It needs to be taped shut and signed by collector
Chain of custody
Used to present credible evidence in court
1. a person bags evidence, marks it for identification, seals it and signed it across the sealed edge
2. Signed over to a technician in a lab for analysis who opens it but not on the sealed edge
3. After analysis the technician puts it back in the evidence bag, seals it in another bad and signs evidence log
Primary Crime scene vs Secondary Crime scene
Primary scene is where the crime is committed
A second scene would be the home of the suspect
What does crime scene reconstruction involve?
You need to form a hypothesis on the sequence of events from before the crime was committed through its commision
What is a bindle and what is it used for?
A bindle is a paper bag used for transporting and holding evidence
Why is oblique lighting important?
This makes it so that evidence is easier to see from the naked eye
What guidelines must a judge follow to determine the admissibility of evidence.
Falsifiability- refers to testing new theories and methods (repeatable results are valid)
Known error rates
Peer review
General Acceptance
What does the medical examiner do? What’s another term for a medical examiner?
Forensic pathologists, who have specialized training in death investigation
Who makes up the crime scene investigation team?
crime scene photographers and evidence collection personnel specializing in gathering specific evidence such as latent print
What is an exemplar?
legally admissible authentic samples of handwriting used for comparison with questioned writing
What is the significance of the Frye Standard and the Daubert Ruling?
Frye Standard: Used to determine the admissibility of an experts scientific testimony
Daubert Ruling: Judge determines whether an expert witnesses scientific testimony is based on scientifically valid reasoning that which can properly be applied to facts at issue
How can you tell if a crime scene is staged
Initially all death crimes are treated as homicide
See if wounds could be easily self inflicted
Establishes a victim profile
Behavior before event
Reconstruct the event
