chapter 3 forensics

class physical evidence

low certainty, can only link to a group since its mass produced and widely found

individual physical evidence

high certainty, can be traced to a single source

examples of class physical evidence

blood type, hair/eye color, paint, fibers, new shoes/tires/tools

examples of individual physical evidence

fingerprints, DNA, fired bullets

main difference between class and individual evidence

degree of certainty about what the source is

direct evidence

physical recording of events, eye witness who saw/has info about evidence gives testimony

transient evidence

temporary, easily changed/lost

examples of transient evidence

odor, temp, imprints

pattern analysis

aids reconstruction, can’t be packaged, must be documented, often destroyed after collection

reconstruction patterns

blood spatter, glass fracture, tracks, tire marks, clothing, projectile trajectory, fire burn marks, gunshot residue, wound/damage

conditional evidence

produced by specific actions/events at scene

examples of conditional evidence

lights on/off, door open/closed, locked/unlocked, position of body/object

indirect evidence

implies a fact, allowing inferences about an event/circumstance

physical evidence

any object that can help prove a crime occurred

identification

determining a substances physical/chemical identity

comparison

determining whether 2+ objects have a common origin

product rule

calculating the chance of unrelated events occurring together

IAFIS

integrated automatic fingerprint identification system

CODIS

combined DNA index system

NIBIN

national integrated ballistics information network

PDQ

international forensic automatic paint data query

SICAR

shoeprint image capture and retrieval

NamUs

national missing and unidentified persons system

how does a database get used?

contains various evidence, used digitally to rank best to least match

reason 1 why the atlanta case is famous

unusual to convict someone only on fiber evidence

reason 2 why the atlanta case is famous

first time the FBI used BSU to catch a serial killer “at work”

reason 3 why the atlanta case is famous

only 2 of 26+ cases solved