Arson - Forensics
Where did Julio get the accelerant? What was suspicious about him?
Local gas station His home & shoes smelled of gasoline
Vaporization
Liquid changes to gas
Direct extraction procedure (2)
1) Remove vapors w/ syringe 2) Analyze vapors w/ gas chromatography
Psychology of an arsonist (3)
1) Sense of power 2) Emotional high 3) No typical arsonist. Only possible characteristics
How should fire evidence be collected? (4)
1) Begin immediately; no warrant needed 2) Collect 3-4 liters of ash from point of origin & other suspected areas 3) Use portable vapor detectors (sniffers) 4) Use trained dogs to sniff
What is the function of a fire investigator? (4)
1) Collect evidence quickly before it's lost 2) Find fire's point of origin 3) Examine possible causes (accidental vs. arson) 4) Classify fire
What three things does combustion involve?
1) Combustion reactions 2) Heat of combustion 3) Exothermic reactions
Why is arson difficult to prove? (4)
1) Crime usually carefully planned 2) Fire destroys evidence 3) Arsonist leaves scene before anyone notices fire 4) Extinguishing the fire also destroys evidence
Six motives for arson
1) Financial gain (insurance fraud) 2) Revenge, spite 3) Excitement 4) Vanity, hero syndrome 5) Crime concealment (destroy evidence) 6) Vandalism
What are the four igniters (causes of fires)?
1) Matches 2) Cigarette lighters 3) Molotov cocktails 4) Faulty electrical wiring
List fire classifications (4)
1) Natural 2) Accidental 3) Undetermined 4) Deliberate
Parts of the fire tetrahedron (what's needed to start a fire & keep it burning)
1) Oxygen 2) Fuel 3) Heat 4) Chain reaction
How should the fire control sample be collected? (4)
1) Place each sample in its own container 2) Collect a substrate control 3) Comparisons to the substrate control can help prove an accelerant was used 4) Some products may look like accelerants when burned
Passive extraction procedure (4)
1) Suspend a charcoal-coated strip inside can 2) Replace lid 3) Heat container 4-16 hrs at 50-80 deg. C 4) Charcoal absorbs the vapor
How should debris be packaged? (2)
1) Use airtight containers like a new, clean, paint can & lid 2)Leave head space at top of can
How many people were trapped and died?
87 of the 90
Fire (chemistry of it)
A rapid oxidation reaction that involves a combustible material
Substrate Control
A similar but uncontaminated sample Used for making comparisons
What does the streamers pattern indicate?
Accelerant was used to spread fire from one area to another
Faulty electrical wiring
An arc causes a predictable pattern
Hydrocarbon
Any compound consisting only of hydrogen & carbon
Accelerant
Any material used to start/sustain a fire. Most common is combustible liquids
Why did Julio set fire to the Happy Land Club in Bronx?
Because Lydia broke up with him
Spalling Pattern
Breaking away of layers of concrete due to exposure to high temperatures
Pool or plant Pattern
Burns in a puddle configuration
Classic V Pattern
Burns narrower at bottom, spreads outward as it rises.
Alligatoring Pattern
Burns resemble scales of an alligator
Streamers Pattern
Burns show a trail from one area to another
Inverted Cone Pattern
Burns wider along floor & narrower as it burns upward
Undetermined fires
Cause unknown & can't be identified
Natural fires
Caused by acts of nature (lightning strike, intense sunlight)
Exothermic Reaction
Chemical reaction that releases heat
What does an inverted cone indicate?
Could be caused by accident or by accelerant poured along floor
Pyrolysis
Decomposition of organic matter by heat in the absence of oxygen
What does arc damage indicate?
Electrical fire or a fire that's burned through wire insulation
Heat of combustion
Excess heat given off in a combustion reaction
Examples of hydrocarbons
Gasoline Kerosene lighter fluid
Deliberate fires
Intentionally set. Not all arson. Could be a campfire that spread out of control.
Who was primarily involved in the Happy Land Fire?
Julio Gonzalez and Lydia Feliciano
What are the possible characteristics of an arsonist? (11)
Less than 25 yrs Father gone Domineering mother Academically challenged Emotionally/psychologically disabled Unmarried Living w/ parents Inadequacy, insecurity Fascination w/ fire Alcoholism Parental neglect/abuse
Molotov cocktails
May leave glass fragments
What happens in a gas state?
Molecular bonding is weaker
What are most accelerants (concerning hydrogen & carbon)?
Most accelerants are hydrocarbons in a gas state
Matches
Often burns in fire Most common Don't leave much evidence of match used
Cigarette lighters
Often removed by arsonist
What does a Classic V pattern indicate?
Ordinary burn pattern No accelerant used
Combustion Reaction
Oxidation reaction involving oxygen Releases heat & light
What does a spalling pattern indicate?
Possible use of accelerant, but not absolute
What does alligatoring indicate?
Possible use of accelerant, but not absolute
What does a pool or plant pattern indicate?
Poured accelerants accumulated in a pool at the lowest point
Arc Damage Pattern
Spark caused by a release of electricity
Oxidation reaction
The complete or partial loss of electrons or gain of oxygen
Arson
The intentional & illegal burning of property
Flashpoint
The lowest temperature at which vaporization occurs in an accelerant
Accidental fires
Unintentional & explainable Caused by faulty wiring, malfunctioning appliance, human carelessness
Vapors and pyrolysis
Vapors given off from resins in wood are flammable and will burn
