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Arson and Fire Investigation

Arson and Fire Investigation

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Arson and Fire Investigation

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  1. Arson and Fire Investigation

  2. Summary Fire: What is fire? • Collecting evidence • Analyzing evidence Explosives: What are they? • Collecting evidence • Analyzing evidence

  3. 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.

  4. Fire Fire: rapid oxidation with evolution of heat and light.

  5. Fire Four components of fire: • Fuel • Heat • Oxygen • Uninhibited chemical chain reaction

  6. Fire Four components of fire: Fuel: can be solid, liquid or gas • 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.

  7. Fire Four components of fire: Heat: Temperature Oxygen: found in air; can be used up in closed in spaces. Chemical Chain Reaction must: • The oxidation reaction (burning) must produce enough heat to maintain burning • The fuel mass must be vaporized and drawn up into the flame.

  8. Fire Fire Investigation: First the point of origin is determined: • Where the fires starts • Usually contains the most damage. Once point of origin is determined, the cause of the fire is determined.

  9. Fire > Investigation Cause of Fire: • Natural • Accidental • Undetermined • 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)

  10. 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 Unburned portions of chemical and electronic devices may be left behind.

  11. Fire > Collection Collection of Evidence Even in a large fire, accelerant residues of flammable liquids may be left behind. • Common: gasoline, kerosene, fuel oil • Rarer: alcohol, paint thinner Unusual burn pattern may suggest use of liquid accelerant.

  12. 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.

  13. Fire > Collection Containers for Evidence • Metal cans: airtight, but old cans might rust • Glass Jars: rubber or glued liners may interfere with results. • Special airtight plastic evidence bags: must be properly sealed

  14. Fire > Collection Collection of Evidence • Along with sample from point of origin, a control sample should be collected. (material from a different room/location) • Carpet fibers (synthetics) may be “petroleum” based. • Obviously, evidence collection documented with photos, sketches, etc.

  15. Fire > Analysis Analysis of Accelerants Gas Chromatography separates components and Mass Spectrometry identifies the components.