The Crime Scene: Chapters 2 and 3 Flashcards
buccal swab
- a swab of the inner portion of the cheek
- cheek cells are collected to determine the DNA profile of an induvidual
chain of custody
-a list of ALL people who came into possession of an item of evidence
-anyone who was known to be working with/or at the crime scene
rough sketch
-a draft representation of all the essential info & measurements of a crime scene
-drawn at the crime scene upon arriving
final sketch
-a precise rendering of the crime scene
-drawn to scale with exact measurements
physical evidence
-any object that can establish that a crim was committed
-any object that can link a person to the crime scene
standard/reference sample
-a sample of physical evidence whose origin is known
-used to compare samples with unknown origins to determine if they are similar
ex: hair collected from suspects (reference sample) can be compared to hair found at the crime scene
substrate control
-refers to an uncontaminated surface that is close to an area where physical evidence had been placed
-used to ensure that the surface on which the sample of the physical is placed does not interfere with the laboratory testing
class characteristics
-properties of evidence that can be associated with a general group
-they never originate with a single source
-ex: finding the specific shoe type/brand based on a shoeprint
individual characteristics
-properties of evidence that can be attributed to a common origin
-had an extremely high degree of certainty
-ex: matching a specific mark or tear on a shoe to a shoeprint at a crime scene
comparison
-the process of confirming whether 2 or more objects have a common origin
identification
-the process of determining a substance’s physical or chemical identity
-ex: drug analysis, species determination, explosive residue analysis, etc.
product rule
-you can find the overall frequency of occurrence for a genetic profile by multiplying the frequencies of independent markers together
-determine the probability of each characteristic, then multiply each frequency together
-the more factors means the greater chance the samples have the same origin
[crime scene] reconstruction
-the method used to support the sequence of events by evaluating physical evidence and recorded statements
-by evaluating evidence and listening to witnesses/suspects, an investigator can recreate the crime scene to discover more about the situation that can’t be determined through evidence
IAFIS
Integrated Automated Fingerprint Identification System
-the national fingerprint database that allows for comparison of fingerprints collected at crime scenes
-over 750 million known prints
CODIS
Combined DNA Index System
-allows for the electronic exchange of DNA profiles for comparisons in investigations
-used by federal, state, and local crime labs
