forensics - unit 1

crime scene photography

crime scene photography

• show the scene exactly as you first saw it

• if something was moved before you arrived, don’t try to reconstruct the scene

• be careful not to destroy evidence

• take photos of the exterior

• begin with a view of the entrance and take photos of all walls

taking crime scene photos of evidence

take 3 shots of each piece of evidence

1. mid-range shot: show how the item is related to its surroundings

2. close up shot: bring out the details of the item - one with a measuring device and one without

sketching a crime scene

make an accurate rough sketch, note the direction and the scale of distance, include relevant objects and make a final copy of it for trial on a computer

searching for evidence at a crime scene

use a grid, strip/lane or a spiral search pattern, use a flashlight to find hair and fibers

securing collected evidence

properly package, seal, and label ALL evidence

securing liquid evidence

use an airtight, unbreakable container, like a plastic jar

securing wet evidence (biological)

dry out in a breathable container (such as a paper bag)

securing dry evidence

put trace evidence in a bundle and then in a plastic or paper container

direct evidence

first hand observation (eyewitness or video)

circumstantial evidence

indirect evidence, implies a fact but doesn’t directly prove it (literally everything: DNA, glass)

individual evidence

evidence that narrows the suspect pool to an individual person/thing (like hair with root DNA, a specific foot print that shows arc of the foot and a walking patter - perhaps a limp)

class evidence

evidence that narrows down the suspect pool to a group of people/things (ex: a type of shoe)

The ability to establish the exact whereabouts of an item of evidence and under whose control it was from its collection at the crime scene to its presentation in the courtroom and everywhere in between is called

chain of custody

The location where the crime took place

primary crime scene

"With contact between two items, there will be an exchange." This is known as _____

Locard’s exchange principle

The first officer arriving at a crime scene, after providing or obtaining medical assistance for the injured and effecting an arrest of suspects (if possible), should immediately:

secure the scene

a location other than the primary crime scene, but that is in someway related to the crime, where evidence is found

secondary crime scene

5 basic services provided by full-service crime lab

physical science unit, biology unit, Firearms Unit, Document Examination, Photography unit

physical science unit

Incorporates the principles of chemistry, physics, and geology to identify and compare physical evidence

biology unit

investigate blood samples, body fluids, hair, and fiber samples

Firearms Unit

investigates discharged bullets, cartridge cases, shotgun shells, and ammunition

Document Examination

handwriting analysis and other document issues

Photography unit

specialized photographic techniques for recording and examining physical evidence

how many people are needed for a live line-up?

6

how many minimum people are needed for a photo line-up?

8

what are the 3 facets of guilt that detectives are looking for?

means, motives, and opportunity

common staged crime scenes

arson - to cover up bankruptcy or murder

suicide - to cover up a murder

burglary - to collect insurance money

how to secure the collected evidence

• properly package, seal, and label ALL evidence

• liquid: airtight, unbreakable container

• wet/biological: dry out in a breathable container'

• dry: bindle → plastic or paper container

• seal with tape and label with pertinent info

civil law is also known as

private law

criminal law is also known as

public law

misdemeanor

a minor crime such as theft, minor assault and battery, or possession of small amount of illegal drugs

felony

a major crime such as murder, rape, armed robbery, serious assault, dealing illegal drugs, fraud, auto theft, or forgery

Miranda v. Arizona (1966)

before a law enforcement officer may question a suspect regarding the possible commission of a crime, they must inform the detainee about their Miranda rights, and make sure the detainee understands them

all crimes are violations (breach of a right, duty, or law). what are the three types?

infraction, misdemeanor, felony

infraction

minor offense/petty crime, penalty is usually a fine or community service

federal rules of evidence

probative, physical, hearsay