Crime Scene final

Evidence Linkage Triangle Corners

Crime Scene, Witness, Suspects

Evidence Linkage Triangle Center

Physical Evidence

Locard's Exchange Principle

Every contact leaves a trace

6 Things Physical Evidence Can Do

Prove a crime has been committed/establish key elements of a crime

Place the suspect in contact with the victim or crime scene

Establish identity of persons associated with a crime

Exonerate the innocent

Corroborate victim's testimony

Lead to the admission or confession of a suspect

If it's not document it

didn't happen

Types of Search Patterns on Land

Grid

Spiral

Zone

Line

Point to point

Grid Search on Land

Search in grid pattern N-S and then E-W

Interior areas

Spiral Search on Land

Search in spiral pattern inside to outside or outside to inside

Circular rooms

Zone Search on Land

Divide room into zones and give zone assignments

VEHICLE, ROOM

Line Search on Land

Search in straight line as group on hands and knees

outdoor scene

Point to Point Search on Land

Search in a line that connects the points of evidence

smaller scenes with clear connection

Purpose of Midrange/Evidence Establishing Photographs

show where the evidence is in relation to the scene/parts of the scene and have measurable distances

Most evidence from a sexual assault is lost after

36 hours

3 Reasons Physical Evidence is Collected from Sexual Assaults

To establish sexual contact occurred

To establish non-consensual contact occurred

To establish identity of suspect

Active Animal Abuse

hitting, kicking, beating, burning

Passive Animal Abuse

Starvation, not taking to the vet

MacDonald Triad

fire starting, cruelty to animals, and bed wetting past age 12 shows markers to become a serial killer

How to Process a Live Animal

Photograph all sides of animal

Paw prints

nail scrapings/ clippings

Fur sample/ swab

Mouth swab

Three Roles Animals May Play at Crime Scene

Victim, Suspect, Witness

Hand Search Underwater

Hard to tell what you are touching in low to no visibility, hard to tell if it is something you have already touched without a clear pattern

Need to describe to someone who may not understand/may be hard to describe

Types of Underwater Search Patterns

Random

Sweep

Parallel

Circular

Snag

River

Random Underwater Search

Not a pattern

For maximum visibility in small area

Sweep Underwater Search

Accessible shoreline/dock/pier/bridge

Large sweeping arcs tethered to a rope

Parallel Underwater Search

Free of obstructions

Tender moves back and forth between markers

Circular Underwater Search

Tethered to boat based in center of circle

Snag Underwater Search

arch, parallel, circular pattern

large area searched in short time

River Underwater Search

Dependent on current and land based anchor point

swift water operations

Package Handgun Underwater

Package underwater in tupperware with water in typperware

Control for Underwater Packaging

Sample of soil under what was packaged

Process Through Which a Vehicle Will Sink

Front sinks first because engine and water comes up through vents

Anterior

front

Posterior

back

Medial

toward midline

Lateral

away from midline

Proximal

away from extremities

Distal

toward extremities

Superficial

on the surface

Rule of Nines

used to estimate the total surface area of the body burned

Fatal Burn Percent in elderly/children

20%

Fatal Burn Percent in Adults

50%

Manners of Death

Natural, Suicide, Homicide, Accident, Undetermined

Cause of Death

Disease or injury that led to death

gunshot wound, COPD

Mechanism of Death

Physiological/Medical reasoning for death

shock, cardiac arrest, hemorrhagic arthymia

Adipocere

waxy/grave wax

white/gray wax to fatty tissues

3 months to develop

warm area, absence of oxygen, high moisture

Marbling

anerobic bacteria in abdomen spread via blood vessels

take on purple/ green color

typically on trunk and extremities

Skin Slippage

Epidermis separates from dermis in moist or wet habitats

degloving for fingerprinting

Rigor Mortis

Stiffness of the body starting in extremities

begins 2 hours, set 8-12 hours, gone after 24 hours

Livor Mortis

Blood settles where gravity pulls it

set about 8 hours after death

Algor Mortis

Cooling of body after death

Equilibrium 18-20 hours after death

Blunt Force Trauma Finding

Tissue bridging

Components of GSR

barium, antimony, lead

Cut Indentifier

longer than deep

Stab Identifier

deeper than long

Three Classes of Targets

Fixed

Movable

Stationary

Fixed Target

By design is fastened to an area and will not move

walls, floors, ceilings, trees, telephone poles

Moveable Target

By design is capable of moving

Vehicle, furniture, people

Stationary Target

Considered moveable but at a specific point in time is not moving

vehicle, bike, train

Types of Targets

Yielding

Frangible

Non-yeilding

Yielding Target

surface which bends or stretches upon application of force

wood, drywall, sheet metal

Frangible Target

Subject to crumbling or breaking upon application of force

cinder blocks, bricks, pavers

Non-yielding Target

Not significantly accepted by application of force

stone, marble, heavy steel

French Fry Relating to Shooting Documentation

Compressed and punched out section of foam padding that creates a french fry shape

Kinetic Energy as Related to Shooting

energy the bullet possesses due to motion

Perforation

Going through a wall and the opposite wall

Penetration

Going into but not through a wall

Embedding

Bullet is protruding from wall

Does not go into wall

Spall

Penetrates and knocks plaster off the opposite wall without going through it

Deflection

bullet strikes the wall and changes direction

Obtaining track width measurements on vehicles

measure from center of tire to center of opposite tire

Obtaining wheel base measurements

measure from center of front axle to center of rear axle

Contact gunshot wound indicator

Stellite Tear

Blood Stains on Smooth Surface vs Rough

Smooth surface has less satellite spatter

Primary Goals for Managing Mass Casualty

Secure the Scene

organize personnel

render aid

Expiration blood pattern

blood coming out of throat/mouth

coughed up, etc

Shape of Bloodstain based on Angle of Impact

as an angle becomes more acute it becomes more elliptical

Limitations to Ejection Pattern Analysis

Type of firearm

movement of shooter

physical orientation of shooter

physical orientation of firearm

ground surface

Cast Off Pattern

Created when blood is flung or projected

Always one less than number of stabs/hits

Transfer Pattern

Transfer of blood from one object to another in recognizable and discernable pattern

Fly Spot

Flies get blood on them or ingest blood and then throw it up, moves blood to where it wasn't before

Three Types of Clandestine Lab Operators

Small Scale

commercial

educational

Small Scale Operator

drug user selling his own product to support his habit

Commercial Operator

Manufactured for financial gain

May or may not be users

Educated Operator

Least encountered type

Formal chemistry training

Clandestine Lab Requirement Triangle

Equipment, Knowledge, Chemicals

Best source of information in the clan lab

the cook

Three Chemical Requirements for Clan Labs

Precursors, Reagents, Solvents

General rule of thumb for clan labs

if you smell it, it is dangerous

Mass Fatality

more dead bodies, body parts, etc than can be identified with available resources

Mass Casualty

number of victims exceeds resources available

Incident Command System

Most common method for incident management in US

Leading Edge

portion of defect produced by initial contact between bullet and target surface which produces a shoulder/impression

Lead in Mark

Elongated deposition of bullet transferred as the bullet makes contact at a shallow angle

Boat Wave Fracture

Paint on sheet metal fractures in a characteristic and reproducible way

Pinch Point

Small area of survivable paint that was pinched between the bullet's initial contact and the sheet metal

Question 45 on exam

Spatter or Nonspatter

\_____ in ____ women have experienced sexual violence in their lifetime

1 in 3

\_____ in ____ men have experienced sexual violence in their lifetime

1 in 4

Mark from lightning

Litchenberg Mark

Level of ____ in eye can assist in determining death

potassium

Pungent smell of decomposition

Indole, skatole, putrescine, and cadaverine