Transcript Arson

Arson
Fires deliberately set with
criminal intent
“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. Financial stress -profit
2. Pure fraud -profit
3. Third party arson-profit
- eliminate competition
- Labor- management problems
4. Revenge, spite, jealousy
5. Vandalism
6. Conceal a crime
7. Pyromaniac, schizophrenics
- 13.4% of arsonists are schizophrenics
8. Hero fires 1. covering their tracks
- cover theft or murder
Basic Questions to Ask
About the Fire
• Where was the point of origin?
• 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. Witnesses
2. Firefighters
3. Insurance personnel
4. Business associates, creditors, competitors
5. Media
6. Medical examiner or coroner
7. Suspect
8. Owner
9. Informant
Types of fires
A. Accidental
B. Intentional (incendiary)
C. Natural (lightening)
LIGHTNING
STRIKE
Accidental causes
• Electrical system
• Appliances, equipment
• Gas leaks
• Heating units
• Sunlight
• Matches
• Smoking
Bathroom
Accident
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
GAS
TRAILERS
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
Fire
Tetrahedron
Extinguishing fires
When using a fire extinguisher, always remember
the mnemonic PASS
P - Pull (pull the pin that locks the handle)
A - Aim (aim the nozzle at the base of the fire)
S - Squeeze (Squeeze the handle to discharge the
extinguishing agent)
S - Sweep (Sweep the nozzle from side to side,
to cover the fire)
Bright yellow fire with black smoke
Electrical
Fire
Home
Arson
EXTERIOR
GARBAGE
CAN FIRE
FATAL
ACCIDENT
VEHICLE
ARSON