Transcript Arson

Arson
“Fire”
Ashes denote that fire was;
Respect the grayest pile
For the departed creature’s sake
That hovered there awhile
Fire exists the first in light,
And then consolidate
Only the chemist can disclose
Into what carbonates.
By Emily Dickenson from Poems
Reasons for arson
1.
2.
3.
Financial stress -profit
Pure fraud -profit
Third party arson-profit
- eliminate competition
- Labor- management problems
4.
5.
6.
7.
Revenge, spite, jealousy
Vandalism
Conceal a crime
Pyromaniac, schizophrenics
- 13.4% of arsonists are schizophrenics
8.
Hero fires1. covering their tracks
- cover theft or murder
Basic questions to ask
about the fire
1. Where was the point of origin?
2. What was the cause of the fire?
Conducting a fire investigation
• Building must be safe --> Enter building only
when you have the OK from structural engineer
• Accelerants will evaporate quickly so look for
these first
• Locate point of origin : where fire started
• Collect samples of accelerants, etc…
• Interview witnesses
– Where did you see flames first?
– Was there a distinct color to the flames/smoke?
• ex. Gas produces a yellow flame/ white smoke
– Did you see any suspects near the scene?
Michigan vs. Tyler 1978
• Once in- firefighters may seize any
evidence in plain view
• No warrants needed to remain in building
for reasonable time to investigate crime
• Fire department must be on scene during
investigation
• Once leave the scene- need a warrant to
return
Who is interviewed after a fire?
1.
2.
3.
4.
5.
6.
7.
8.
9.
Witnesses
Firefighters
Insurance personnel
Business associates, creditors, competitors
Media
Medical examiner or coroner
Suspect
Owner
Informant
Types of fires
• A. Accidental
• B. Intentional (incendiary)
• C. Natural (lightening)
Accidental causes
•
•
•
•
•
•
•
Electrical system
Appliances, equipment
Gas leaks
Heating units
Sunlight
Matches
Smoking
Why is it pointless to burn a
building to conceal a homicide?
Cremation needs 1500 F for several hours
A fire burns from 500-2000 F, but doesn’t
last long enough to cremate the body.
Locating point of origin
1. Know how fire moves
– Sideways and up from point of origin
– Affected by:
•
•
•
•
stairwells
chemicals in synthetic carpet
decorations
stored flammables
Locating point of origin
2. Most damage is found near the point of
origin
3. Look for V pattern of burned material
4. Steel buckles under extreme heat
5. Spalling (cracking and flaking) on walls
and floors indicate high heat
Locating point of origin
6. Charred wood may have an alligator
appearance… smaller scales near the
hottest part of fire
7. Check the time smoke detectors went off
through the building
8. Look for areas of severe burns in
flooring… may indicate location of
accelerant.
Locating point of origin
9. Look for plants - material placed around
the ignition device to feed the flame
ex. Newspapers, wood
shavings, rags
10. Look for trailer – used to spread the fire
- may connect plants
Igniters
•
•
•
•
•
•
•
wiring
oil lamps
candles
cigarettes
fireplaces
timers
spontaneous combustion
Spontaneous Combustion
• An internal chemical reaction that starts a
fire (rare)
• Combustible materials in enclosed space
ex. Oil-soaked rags in small pantry
Matches
• Heads of matches have diatoms
• Diatoms= single celled organisms with
cells made of silica (tough component that
can survive fire)
• Different manufacturers use different
species of diatoms
Accelerant
• Makes the fire burn faster
1. Solids- paper, black powder, kindling
wood
2. Liquids- gas, kerosene, alcohols, paint
thinners
3. Gases- natural gas, propane
Collecting Samples
• Samples near point of origin taken for
chemical analysis
• May use trained dogs
• Place samples in airtight container
Signs of accelerants
• Flammable liquids flow down, heat travels
up
• Charring on bottom of furniture, etc..
deeper than charring on top
• Clean floor &rugs; pattern may appear
• Check baseboards, sills: liquid runs under
and chars the bottom
• Check corners… floors rarely level
Collecting Samples
• Take control samples from unburned area
• Test for hydrocarbon residues in the air
Detection of accelerants
• Human olfactory sense (limitations)
• Scent dogs
• Chemical color tests
• Some dyes turn red in the presence of
hydrocarbons
Homicidal Fires
• Was the victim alive when the fire started?
• Determine cause and manner of death
Medical examiner looks at:
a. Position of the body
b. Carbon monoxide levels
c. Presence/absence of soot in lungs
- if soot present, the person was
alive and breathing at the time of
the fire.
d. Nicotine levels in urine (tells if victim was
a smoker… for smoking in bed cases)
Asphyxia
Asphyxia = suffocation
•
•
From inhaling smoke and CO
Normal Carbon monoxide level is less
than 5%
•
Slightly higher in smokers
•
45-90%- asphyxiation
CO levels
• 20%-dizziness, confusion
• 35%- weakness, loss of coordination,
Disorientation
• 50%-loss of consciousness
Autopsy signs of CO poisoning:
• CO combines with hemoglobin to form
carboxyhemoglobin (bright red)
• If CO level is low and no soot in lungs
dead before fire
Arson Websites
• http://www.interfire.org/trainingcenter.asp
• http://www.tcforensic.com.au/docs/article1.
html