Chapter 8: Homocide Crime Scene Search

warrantless search may be conducted when:

looking for persons needing help and suspects

evidence may be lost, destroyed, or lose value if not seized

Mincey v Arizona (1978)

emergency/ exigent circumstances

evidence in plain view

post arrest search of individual

consent

Exceptions to 4th Amendment

threats to life or safety

destruction/ removal of evidence

escape

What constitutes an emergency?

temporary in nature

odors, temperature, imprints/indentations, markings

Transient Evidence

produced by contact

blood spatter, glass fracture, fire burn patterns

Pattern Evidence

Caused by action or event

(lighting conditions, odor, color, direction of smoke, location in relation to body)

Conditional Evidence

produced by physical contactof persons or objects or b/w persons or object

Transfer Evidence

crime scene

victim

suspect

Linkage Concept

used in large open areas

quick to conduct

used by 1 or more officers

Strip Method

"circle method"

effective in small areas

overlooked evidence

begin at perimeter and work in

Spiral Method

searches gathered at center and move out

destroy evidence gathered at center

overlooking evidence

Wheel Method

best for large areas

area covered twice

diff. perspectives of evidence

Grid Method

area divided into squares/sectors

squares subdivided

most effective in indoor scenes

Zone Mehtod

quickest/ easiest 4 outdoor scenes

persons lined up and walk in parallel line

Line Method

produce high energy beam light causing flourescent in certain materials

alternate light source, portable and cheaper

provide several wavelengths of light

Lasers and Alternate Light Sources

considers location, size, shape, distribution, and other physical characteristics

may be classified

Bloodstain Pattern Analysis

no defined borders (where to start and end)

vulnerable weather condition no electricity, running water

daylight is limited

Problems w/ Outdoor Scenes

residue consists of:

barium

antimony

lead

(also found in fertilizers so look where concentrations are)

Three common elements found in gunshot residue

particles can be easily removed (4 hr. limit)

.22 caliber ammunition contains no barium or antimomy

Disadvantages in testing gunshot residue

EMS

law enforcement

lab workers

immunization must be offered to these people

People at high risk for exposure

Preventions?

blood/body fluid into cuts or skin

needle sticks

mucous membranes

Three ways one is exposed to bio-hazards

Chapter 9: Estimating Time of Death

aid in conviction of murderer

eliminate suspect

break alibi

substantiate statements of witnesses

Importance of estimating death?

gives estimated time of death

usually out w/i range of hours depending on condition of body

process subject to error based on amount of info.

Pathologist

most reliable indicator of time of death up to 18 hours

done by insertion of thermometer into liver

compared to ambient temperature

Core Body Temperature

stiffening/contraction of body muscles related to chemical changes

begins 2 to 4 hours after death

complete in 8 to 12 hours (spread throughout whole body)

1st noticed in neck and jaw, and smaller muscles

begins disappearing in about 18 to 36 hours

completely gone in 48 to 60 hours

poorest guage for estimating time of death

Rigor Mortis

stiffening of hands/arms after death

usually clutching weapons in hand

reamins until putrefaction

cannot be duplicated

(gunshot suicides)

Cadaveric Spasm

a.k.a "livor mortis"

caused by pooling/settling of blood w/i vessels from effects of gravity

depending on position of body

begins 30 min. after death

full development 3 to 4 hours

8 to 10 hours becomes fixed- no longer change

Postmortem Lividity

tells how long person has been dead

tell whether person was moved after death

Importance of Postmortem Lividity

pressure put to area of lividity

coloration reappear

4 to 5 hours pressure doesn't cause this

Blanching

Cherry red livor mortis (see mostly)- carbon monoxide, cyanide, cold conditions

Little or no- loss great deal of blood

Deep purple- asphyxia, heart failure

Types of Discoloration

combination of 2 processes:

autolysis- breakdown of cells and organs

bacterial action- conversion of soft tissues to liquids and gases

accelerated by heat, slowed by cold, stopped by freezing

apparent after 24 hours

produces gases distort and discolor tissues

Putrefaction

temperature

ground conditions

amount of clothing

size of body

very inaccurate guage of time of death

Variables of Putrification

abdomen swells

fluid emits from mouth and nose

rectum may empty

skin blisters w/ watery fluid

gases appear on skin

After several days of putrefaction

greasy, soap develops on surface of body

develop in warm weather

forms in 6 to weekscovers face and buttocks

seen everywhere

Adipocere

occurs when death is in hot, dry place with adequate circulation of air

fluids rapidly absorbed

body tissues become dry

delays putrefaction

body preserved for years

Mummification

collect maggots from remains, place in hot water then alcohol (75%) , seal bottle

maggots should be collected from each infestation site

beetles inhabit a body

Enthomologist

(Insects)

vegetation under body compared to vegetation in area

samples of sod and vegetation under body should be collected and control samples

Botanist

(Plants)

decomposed more slowly to one on land due to water temp. being lower than air temp., and lack of oxygen

accelerated decomposition- septic tanks or large amounts of water

Bodies in Water

hands swollen after several days

outer layer of skin separates w/i 5 to 6 days

skin hands and fingernails 8 to 10 days

seaweed vegetation on body, and warm water 8 to 10 days

cold water 2 to 3 weeks

Bodies of water general time spans

Chapter 17: Collection of Evidence

be properly identified

show complete chain of custody

material and relevant

meet legal requirements

Procedures for evidence to be introduced at a trial

case #

description of item

location of seized item

date/time of seized item

collecting officer's initials

individual evidence item number

Evidence should be marked with

item should be placed in seperate, clean, properly seized containers

item must be sealed to prevent contamination or loss

item should show proper disposition

records of chain of custody must be kept

(packaging and seperate forms)

Guidelines for seized evidence

could have only come from 1 source

(DNA, fingerprints, handwriting, shoe impressions)

Individual Characteristic Evidence

phenolphthalein (Kastle-Meyer)

blood= pink stain w/i 5 seconds

 chemicals are added: methanol, phenolphthalein, hydrogen peroxide

leucomalachite= blue green color

Orthotolidine= blue color

no DNA testing after this procedure

Field Testing of Blood

bluish-white light

not specific for blood

will react 1:1,000,000 parts blood to water

Luminol

protein reactant

glows more brighter than luminol

reaction photographed

Hemaglow

catalytic reaction b/w hemoglobin in blood and oxygen

produces luminescent stain

requires alternate source of light

reaction lasts longer

Florescein

protein staining die

sprayed or washed onto surface

excess wash of with water

evidence photographed the seized

Amido Black

proten staining dye

sprayed or washed on surfaces

exces washed off w/ glacial acetic acid

evidenced photographed and seized

Coomassie Blue R250

make safe by dropping magazine

photo sketch location

examine fingerprints, blood, trace evidence

(brand name, model #, serial #, shot capacity (# of bullets that can be held), finish, and caliber

Weapons

image analysis system

captures, stores, and analyzes images of bullets and cartridge cases

images read by lasers and coded

results enetered in database

transfer of images for comparison

Forensic Examination

(IBIS) Integrated Ballistic Identification System)

(capture system)

rifling characteristics of fired bullets

characteristics on fired casings

firing pin impressions

breechlock/extractor/ ejector markings

Captures Images of...

Cartridge Casings

database system for images

National Integrated Ballistic Information Network

(NIBIN)

most valuable evidence that can be obtained from homocide scene

Fingerprints

Atomated

Fingerprint

Identification

System

2 databases: offender/forensic file

runs forensic examination

AFIS

plastic-touching soft pliable surface

latent- invisible

patent- contains contaminant transferred to another surface

Types of Fingerprints

The fingers, palms, and soles of feet are considered what?

Friction Ridge Skin

What is the most popular method used at the crime scene?

Powder processing

chemical

reacts to trace amino acids

Ninhydrin

used to develop prints on sticky side of tape

Crystal violet

superglue fuming

adheres to moisture left in prints

done prior to processing bonds to moisture in finger print and bonds to it

Cyanoacrylate esters

coomassie blue R250- cancer causing

Amido Black- preferable; safer

Development of Prints

(enhances blood)

35 mm format or larger

back and white film

use tripod

90 degrees camera lens >90 distortion

use oblique lighting

cast with dental stone

Tire and Shoe Impressions

photograph 1st with and w/o scale

cast tool mark with the use of Mikrosil

Tool Marks

Crime Scene Photography

lead viewer through scene from overrall perspective up to details of specific

items of evidence

Importance of Photographs

having no idea why photograph was taken or what the item is

Identification Problems

one cannot tell right from left up from down

show viewer where item of evidence is located

includes landmark area

Orientation Problems

(evidence establishing shot)

photographs showing altered scenes

overcome by using photograph log

Confusion Problems

photographs of critical items not taken

Incomplete Documentation

what types of crime scene photographs can be taken at the scene?

Overrall

Evidence (establishing close-ups)

depict general condition and layout of scene

1st to be taken

wide angle lens (28mm)

4 corner photos

prior to info. of scales

after scales or #ed placards are put in place

Overrall Photographs

mid-range photos

item depicted is framed in conjunction w/a landmark

use photo placards

#ing system must be used

Evidence Establishing Photos

fill frame of viewfinder of camera w/ items of evidence

provide much detail as possible

should be taken w/ or w/o scales

seized items from scene photos can be taken @ office or lab

Evidence Close-Up Photos

documentation procedure for bloodstain patterns case

highly intrusive; left for last of search

Roadmapping

document scenes ASAP using overrall photos

photo fragile items

document ALL known evidence w/ evidence est. close-up photos

items found later must be recently photographed

create photos clearly demonstrate results of examin. (bloodstains etc.)

use film roll ref. card and photo log

Methodology

does photos accurately rep. scene?

is photo free of distortion?

is photo material relevant to case @ hand?

Admissibility in Court

physical control

light

focus and depth of field

What are the 3 basic aspects of the operation of the camera?

lack of understanding or practice

lack of understanding as to what photos are to depict

Recurring Problems

any shutter speed 1/60th of a second or faster- handheld with firm grip

below 1/60th of a seond- requires tripod

Physical Control

too much light- photo bleached out

too little light- dark photo

fill flash should be used

close-up photos are overexposed (oblique lighting used)

Light

F-stop: how wide lens aperture opens

Depth of Field

used at night or low light scenes

single flash will not illuminate scene

Painting w/ Light

used as a supplement to still photography

precautions (does not focus quickly as human eye, lighting is necessary, audio)

Video Photography

Chapter 7: Crime Scene Sketch

What are some reasons for sketching at the scene of crime?

supplements (written reports, photos)

present measurements

identify significant items

deletion of irrelevant items

show entire scene at once

2 measurements made from, 1 from each end of an object to a fixed point in diagram

useful for locating furniture

Straightline

2 measurements taken at right angles of item to nearest  2 permanent objects

simplest method

Rectangular Coordinate

measurements are taken from at least 2 or more fixed points to an object in sketch forming a triangle

Triangulation

used for areas w/o good fixed points- fields

straight line drawn and 2 ends of line are measured

line used for ref. point at all other measurements

Base Line

CAD programs used to trace aerial photos

can be taken by investigator of other photographer

can be obtained from planning and development dept. and from other county offices

Aerial Photography

developed for use by surveyors

measurement data downloaded into instrument then computer

once downloaded, sketch automatically generated from info.

Total Station