CRIME SCENE ANALYSIS

Chapter 2

PHYSICAL EVIDENCE Any and all objects

that can establish that a crime has been committed or can link a crime and its victim or perpetrator

Physical evidence that is collected can be analyzed by one of the divisions of the crime lab

http://www.youtube.com/watch?v=awcnMrZiSmU

SECURING THE CRIME SCENE Crime scene must be

secured and recorded Any medical assistance

is given first Tape is used to block

access to crime scene area

Boundaries are determined

Entrance and exit sites are determined

http://www.youtube.com/watch?v=YnQ945PtfiY

RECORDING THE CRIME SCENE Police must record

crime scene in untouched state (before any contamination to crime scene)

Three methods: photography, sketches and notes

http://www.youtube.com/watch?v=KHUmfTM7UoQ

PHOTOGRAPHY Scene must be

photographed without being moved or altered in any way (unless someone needed medical attention)

Crime scene and all adjacent areas

Physical evidence in crime scene and close ups are taken

Digital photos and videotaping can be used

http://www.youtube.com/watch?v=Ei_ROza-l_g

CRIME SCENE SKETCHES Sketch the scene

Rough sketch with accurate dimensions and location of evidence

Finished sketch—more detailed fine sketch to be used as evidence

http://www.youtube.com/watch?v=qtLeko20xec

CRIME SCENE NOTES Detailed description

of scene and location of physical evidence, and who found, and how packaged and marked

Notes can be written or tape-recorded

http://www.youtube.com/watch?v=3kSpY9CA4Cw

DEALING WITH PHYSICAL EVIDENCE—SYSTEMATIC SEARCH FOR EVIDENCE One person in control of

collection to avoid duplicate analysis

Weopons Contact between victim and

suspect evidence Cross transfer of evidence Hairs Fibers Blood Point of entry marks Trace evidence—imprints in

ground Inside and outside of crime

scene should be analyzed http://

www.youtube.com/watch?v=RC4z4t5fGgY&feature=fvsr

COLLECTING PHYSICAL EVIDENCE Trace evidence and things like

clothing that might contain trace evidence are packaged and sent to lab

Fingernail scrapings of individuals are collected

Autopsy is conducted Items from deceased victim

are sent to crime lab: Victim’s clothing Fingernail scrapings Head and pubic hairs Blood Vaginal, anal, and oral swabs Recovered bullets Hand swabsEach piece of evidence is

packaged separately

CHAIN OF CUSTODY

Evidence must be submitted with documentation and labelled to type

Every person who handled evidence between collection at crime scene and presentation at court must be documented

http://www.youtube.com/watch?v=rc-hhmi1-NA

FORENSIC PATHOLOGIST Who? What type of injuries? What caused death? When did injuries

occur? Time of death?—

condition, rigor mortis , livor mortis, algor mortis, potassium levels in ocular fluid

http://www.youtube.com/watch?v=XYEQmgT4nxE&feature=related

Rigor mortis—stiffening of muscles between 24 and 36 hours after death

Livor mortis—settling of blood in areas closest to the ground

Algor mortis—body temp cools after death until it is room temp

FORENSIC ANTHROPOLOGY Identification and

examination of human skeletal remains

Bones reveal age, gender, race, and skeletal injury

May create facial reconstructions

http://www.youtube.com/watch?v=ZsHgv2UnFdc&feature=related

FORENSIC ENTOMOLOGY Used to estimate time of

death or timeline of crime

Bow flies lay eggs of human remains that hatch and consume human organs and tissues

By examining stage of insect development—timeline can be estaablished

http://www.youtube.com/watch?v=6U4ewxenyYU