Forensics: Chapter 3: The Crime Scene

Corpus deliciti

Body of the crime

Authorities must prove

A crime occurred. The person charged with the crime was responsible for the crime

Top reasons for committing a crime

Money,revenge, emotion

Sources of evidence

Body, crime scene, suspects

Crime scene team

A group of professionals trained in a variety of special disciplines

First officer does this

Assess the scene and assist injured
Detain witnesses
Arrest perpetrators
Protect the scene
Take notes

Forms of documentation

Notes,photography, sketches, videos

Line or strip method

Best in large outdoor scenes (parallel lines in 1 direction)

Grid method

Double-line search;effective but time consuming (parallel lines side to side and up and down)

Zone method

Most effective in houses or buildings (looks like a cross)

Wheel or ray method

Best on smaller circular crime scenes (arrows pointed in many directions)

Spiral method

May move inward or outward; best used where there are no physical barriers

Chain of custody

Document documenting everyone who has come into contact with evidence; must be maintained to be able to be used in court


Samples with known origins from suspects or victims!

Druggists fold

Trace evidence is placed on a piece of paper is folded in this manner

Questioned evidence

Evidence with unknown origins

Bloodstained evidence goes in...

Paper bags to prevent growth of mold

Charred evidence is put in...

Airtight containers to prevent evaporation of residues

Medical examiner

Has a degree, not always us citizen, not elected


No training, us citizen, elected official


Physiological reason a person died (what happened to them physically)


What caused the physiological death (cause of physical death)


The term that describes the way the person died (classification of death)

Who collects evidence from a deceased body?

Medical examiner or coroner

Maryland has what?

Medical examiner

What does the final sketch of a crime scene include

Black ink, legend/key, 2reference points, distance measurements

When should notes be taken?

Throughout the entire investigation

Jeffrey MacDonald case

Military police
Poor chain of custody
Not careful at collection
Evidence hidden
MacDonald convicted


Actually proves something

Evidence from a suspected arson must be package in

An airtight container to prevent evaporation of possible fumes

Evidence may be obtained from

Suspects,victims,crime scene

A shirt with blood on it found at a crime scene should be

Packaged in a paper bag to prevent mold and/or mildew

Which search pattern is best used at a crime scene with no physical barriers?



A light used to spot body fluids that appear invisible


A flammable substance used to help start a fire

Modus operandi

Method of operation of a criminal

Controls are collected from..

Known suspects or victims

How should a crime scene investigator document the crime scene?

Utilize as many methods as possible...

Notes include

Date,time, description of location, weather, environmental conditions, description of the crime, location of evidence, the names of all ppl involved

All photographs should include...

A Ruler for scale

Plastic pill bottles/glass vials

Use to contain trace evidence while preventing leaks

Who notifies next of kin?

The medical examiner/ coroner