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Arson Fires deliberately set with criminal intent.

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Presentation on theme: "Arson Fires deliberately set with criminal intent."— Presentation transcript:

1 Arson Fires deliberately set with criminal intent


3 “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

4 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

5 Basic Questions to Ask About the Fire Where was the point of origin? What was the cause of the fire?

6 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?

7 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

8 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

9 Types of fires A.Accidental B.Intentional (incendiary) C.Natural (lightening)


11 Accidental causes Electrical system Appliances, equipment Gas leaks Heating units Sunlight Matches Smoking

12 Bathroom Accident

13 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.

14 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

15 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

16 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.

17 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


19 Igniters wiring oil lamps candles cigarettes fireplaces timers spontaneous combustion

20 Spontaneous Combustion An internal chemical reaction that starts a fire (rare) Combustible materials in enclosed space ex. Oil-soaked rags in small pantry

21 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

22 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

23 Collecting Samples Samples near point of origin taken for chemical analysis May use trained dogs Place samples in airtight container

24 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

25 Collecting Samples Take control samples from unburned area Test for hydrocarbon residues in the air

26 Detection of accelerants Human olfactory sense (limitations) Scent dogs Chemical color tests Some dyes turn red in the presence of hydrocarbons

27 Homicidal Fires Was the victim alive when the fire started? Determine cause and manner of death

28 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)

29 Asphyxia Asphyxia = suffocation From inhaling smoke and CO Normal Carbon monoxide level is less than 5% Slightly higher in smokers 45-90%- asphyxiation

30 CO Levels 20% - Dizziness, confusion 35% - weakness, loss of coordination, disorientation 50% - loss of consciousness

31 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

32 Fire Tetrahedron


34 Extinguishing fires



37 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)


39 Bright yellow fire with black smoke






45 Electrical Fire

46 Home Arson





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