CRIMINALISTICS STUDY GUIDE PART TWO

10/6/25

what are 5 types of search patterns

spiral, line, quadrant, grid, wheel

physical evidence

an object that links to a suspect or victim or proves that a crime happened

3 packaging devices used to collect evidence

vials, paper bags & envelopes

when trace evidence is collected it may be placed on a piece of paper which is then folded in a 

druggist fold 

what information should be included on each piece of evidence?

description of contents, date, time, location, agency & collector’s name, case # and victim’s names 

chain of custody 

chronological documentation that records the how the physical evidence was transferred 

what should the chain of custody include

date & time of transfer, location of transfer, to/from names, purpose of transfer 

3 categories of attacks on labs expertise

tampering, contamination, substitution

what are the 5 national databases

AFIS, IAFIS, CODIS, IBIS, PDQ

AFIS (automated fingerprint identification system) 

matching fingerprints 

IAFIS (integrated automated fingerprint identification system) 

holds fingerprints & criminal history 

CODIS (combined dna index system)

fbi program that supports dna

IBIS (integrated ballistic identification system)

run by ATF (matching bullets)

PDQ (international forensics automative paint data) 

deals with paint 

what does the first officer on the scene do?

assess the crime + assist the injured, detain the witnesses, arrest the perpetrator, protect the scene, take notes

how is the crime scene protected

by tape, ropes & cones

3 things an officer should be alert for

knives, razor blades & sharp objects

why should people wear face shields when entering a crime scene 

so if there’s toxic gas, they can protect themselves 

5 things that should be recorded when doing an observation

who, what, where, when, how

what can be massive to microscopic

trace evidence

systematic

something that follows a planned process to achieve a goal 

crime scene

a physical location that a crime has happened

primary crime scene

the original location

secondary crime scene

an alternate location where evidence can be found

suspect

person who may have committed the crime 

accomplice 

second person associated with the crime 

alibi

where the suspect says they were during the crime

testimonial evidence

verbal evidence 

physical evidence

evidence that’s present at the scene or on the victim 

trace evidence

small amounts of evidence

what steps will an investigator follow to analyze and document a crime scene

interview → examine → document → process 

CSI unit

documents the crime scene in detail and collects physical evidence

district attorney

gets a search warrant from a judge

medical examiner

determines COD

specialists

called in if evidence requires expert analysis

detectives

investigates the crime