Transcript Arson and Fire Investigation

Arson and Fire
Investigation
Summary
Fire: What is fire?

Collecting evidence
 Analyzing evidence
Explosives: What are they?

Collecting evidence
 Analyzing evidence
Fire
Arson - The crime of maliciously, voluntarily, and
willfully setting fire to the building, buildings, or
other property of another or of burning one's
own property for an improper purpose, as to
collect insurance.
Arson – The crime of starting an illegal fire.
Fire
Fire: rapid oxidation with evolution of
heat and light.
Fire
Four components of fire:
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Fuel
Heat
Oxygen
Uninhibited chemical
chain reaction
Fire
Four components of fire:
Fuel: can be solid, liquid or gas
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Fuel can only consumed in the vapor state
 Therefore, solids and liquids must first be
“vaporized”
Burning takes place at the
surface of solids and liquids.
Fire
Four components of fire:
Heat: Temperature
Oxygen: found in air; can be used up in
closed in spaces.
Chemical Chain Reaction must:
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The oxidation reaction (burning) must produce
enough heat to maintain burning
 The fuel mass must be vaporized and drawn
up into the flame.
Fire
Fire Investigation:
First the point of origin is determined:
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Where the fires starts
 Usually contains the most damage.
Once point of origin is determined, the
cause of the fire is determined.
Fire > Investigation
Cause of Fire:
 Natural
 Undetermined
 Accidental
 Intentional
Who investigates the fire?
Often, the Fire Department will have an
investigative team to determine the
cause/origin of a fire. (major events = ATF)
Fire > Investigation
What evidence can be collected?
Paper/Trash – not much evidence
 Accelerant – rapid start
 Chemical device (road flares, propellant)
 Electronic device for delayed ignition
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Unburned portions of chemical and
electronic devices may be left behind.
Fire > Collection
Collection of Evidence
Even in a large fire, accelerant residues of
flammable liquids may be left behind.
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Common: gasoline, kerosene, fuel oil
 Rarer: alcohol, paint thinner
Unusual burn pattern may suggest use of
liquid accelerant.
Fire > Collection
Collection of Evidence
Accelerant remains can be
detected by tracing the point
of origin or canine use.
Object containing accelerant
must be packaged in air tight
container.
Fire > Collection
Containers for Evidence
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Metal cans: airtight, but
old cans might rust
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Glass Jars: rubber or glued
liners may interfere with
results.
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Special airtight plastic
evidence bags: must be
properly sealed
Fire > Collection
Collection of Evidence
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Along with sample from point of origin, a
control sample should be collected.
(material from a different room/location)
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Carpet fibers (synthetics) may be
“petroleum” based.
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Obviously, evidence collection
documented with photos, sketches, etc.
Fire > Analysis
Analysis of Accelerants
Gas Chromatography separates
components and Mass Spectrometry
identifies the components.