L1: Crime scene processing Flashcards
state the objectives of crime scene observation [6]
- establish elements of crime
- establish motive of crime
- maximise collection and preservation of evidence
- establish sequence of events
- link perpetrator to crime
- establish identity of perpetrator
roles of physical evidence [5]
provide investigative leads such as:
1. establish elements of crime
2. establish location of crime
3. link suspect to crime scene
4. reconstruct crime scene
5. find modus operandi of suspect
2 broad types of physical evidence
- those w class characteristics: material can be associated with a group of items that share same properties
- individual characteristics: can be linked to a SINGLE source
define trace evidence
any physical evidence that is very small in size eg. soil, hair, skin cells, glass, fiber
define transient evidence
temporary evidence that can be easily changed or lost if not documented
define conditional evidence
produced by a specific action or event at the scene
define pattern evidence
physical evidence that form a particular pattern
define transfer evidence
contact between 2 surfaces and involves transfer of material across the contact boundary
what is Locard Exchange Principle?
“every contact leaves a trace”
define ‘crime scene processing’
a systematic process of gathering evidence
define chain of custody
documentation to trace the movement of evidence from crime scene to court
define chain of custody
documentation to trace the movement of evidence from crime scene to court
6 steps to crime scene processing
- protection of the scene
- recognition of physical evidence
- marking of PE
- documentation
- collection of PE
- detail search
what info should be noted in the crime scene diary? [10]
- activation [date and time]
- location [address]
- arrival date and time
- taking over scene from who? eg. first responders
- brief facts
- description/observations of scene
- role of team members [photographer, sketcher, fingerprint searcher, exhibit officers etc]
- action taken [date & time]
- scene releases [date, time, to whom]
- departure date and time
role of crime scene photography [5]
- serve as permanent and visual record of the scene
- used for follow-up investigations
- used to refresh memories of witnesses and investigators
- to be used as evidence in court
- assist in fact finding in court proceedings
what should you consider when taking crime scene photo?
- details included in photo shld tell a story.
- sequence of photos
- determine best viewing angle
types of photos to take
- general scene: show general view. include street or block details
- mid-range photos: shows r/s of indiv evidence to other evidence. more details visible. can be linked back to overall general shot to show location within scene
- close up: for key evidence. fill the frame with object of interest to maximise details. use scale if size is impt
types of methods when drawing sketches
- triangulation method
- baseline method
types of sketches
- birds eye view
- elevation view
- exploded view
- 3D view
steps to draw sketches
- start with exterior boundaries
- followed by relevant fixtures
- standard architectural symbols
- evidence indicated by number
indicate compass direction
title, legend, not drawn to scale
pros and cons for using triangulation method to fix location of evidence
pros:
- very accurate method
- better for long distances
- uses 2 fixed points
con: inaccurate if triangle is too sharp or shallow
pros and cons of using baseline method to fix location of evidence
pros:
- simplest method
good for short distance
con: inaccurate if points are too far from baseline or not taken at right angles to baseline
