Module 6
- Created by: JessicaMPascoe
- Created on: 27-03-20 12:13
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- Module 6 - Arson & Explosion Investigations
- 3. Types of Explosions
- Deflagration
- All directions
- Explodes outwards
- Push,shove & heave materials around
- Thermal Process
- Detonation
- Triggered
- Splitting up materials of device
- Releases heat
- Recombination in different forms
- Demolish materials
- Qs asked to determine source of explosion
- Fuel/oxidiser?
- Strength?
- Pressure?
- Source?
- Avoided?
- How did it occur?
- How did the explosion propagate?
- Deflagration
- 5. Case Study: Is Daniel Dougherty guilty of arson?
- Dougherty's Defence
- Time of report, custody over son
- DA = "motive for her lie"
- X evidence of gasoline
- Unreliable inmates
- X evidence of gasoline
- DA = "motive for her lie"
- Time of report, custody over son
- The Case
- they believe DD X arsonist
- Fire = accident, X arrests
- 14 yrs later, DD exwife reports he confessed
- Gasoline
- In custody, DD confessed to inmates
- Gasoline
- 14 yrs later, DD exwife reports he confessed
- Fire = accident, X arrests
- they believe DD X arsonist
- Guilty or Innocent?
- DD awaiting DP, correct?
- JL & AP, found X evidence of arson
- Outdated and unreliable techniques used to determine arson
- 1985, 3 origins. "flashovers" (fire reached heightened intensity)
- Guilty?
- 1985, 3 origins. "flashovers" (fire reached heightened intensity)
- Outdated and unreliable techniques used to determine arson
- JL & AP, found X evidence of arson
- DD awaiting DP, correct?
- The Scenario
- DD skipped meeting in AUG & went to bar
- Verbal altercation w/ GF & went home
- @ home, 2 boys asleep upstairs
- "made dinner and went to bed on the couch"
- Awoke, curtains in flames
- Kids still inside
- Glass window blew out, DD cut w/shrapnel
- Too late for children
- Glass window blew out, DD cut w/shrapnel
- Kids still inside
- Awoke, curtains in flames
- "made dinner and went to bed on the couch"
- @ home, 2 boys asleep upstairs
- Verbal altercation w/ GF & went home
- DD skipped meeting in AUG & went to bar
- Dougherty's Defence
- 2. Investigating the Fire Scene
- 5. Coordinate Interagency Activity
- Effective communication between:
- Fire Personnel, Emergency Medical P. Police & FI
- Effective communication between:
- 4. Establish Security & Control
- FR take control
- Fire out > limit people
- Manage people entering
- Fire out > limit people
- FR take control
- 6. Identify, Collect & Preserve Evidence
- Document EVERYTHING!
- Condition & loc of E
- Initial Analysis of E
- Focus attention of origin
- Fingerprints
- Blood stains
- Signs of struggle
- Criminal evidence
- Samples similar to evidence not affected
- Sealed & labelled containers
- Document EVERYTHING!
- 3. Preserve the Fire Scene
- FR & I take note of:
- Evidence of crime
- Fire Damage
- Witnesses
- Burn Injuries
- Hazardous liquids or contaminants
- Fire Patterns
- Indications of forced entry
- Take note of anything that could contaminate the scene
- Anyone able to walk through the scene
- Tools used
- Vehicles used by R
- Demolition activities and how they affect the fire pattern
- Witnesses & victims leaving
- How the FSA are affecting the scene
- FR & I take note of:
- 7, Prevent Evidence Contamination
- Once fire is suppressed:
- 2. Exercise Fire & Scene Safety
- Evacuate the scene for hazards
- Structural damage
- Remaining fire
- Unprotected Chemicals
- Establish a perimeter
- Keep people informed
- Be aware of tools used
- Evacuate the scene for hazards
- 8. Package & Transport Evidence
- Limit people who contact evidence
- 1. Observe the fire & Scene Conditions
- Who is Responsible?
- First Responders
- Responsibility?
- Fire under control
- Don't collect evidence, report obvious signals
- Investigator should speak with FR to ascertain:
- Overall conditions of structure
- Purpose of Structure
- Anything Unusual
- Condition of fire
- How the fire was suppressed
- Victims or witnesses
- Status of alarms before and after
- Who is Responsible?
- 5. Coordinate Interagency Activity
- 1. Chemistry of Fire
- What is fire?
- 3 Key Variables needed
- High Temp
- Oxygen
- Fuel
- Chemical oxidation reaction
- 3 Key Variables needed
- Extinguishing the fire
- Deprive the fire of its...
- Necessary high temperatures
- Combustible material
- The oxygen it needs to survive
- Water, CO2, Fire Blanket, Baking Soda, Dirt/Sand
- Deprive the fire of its...
- Chemistry of Combustion
- Equations
- C + O2 > CO2
- C + 1/2O2 >CO
- H2 +1/2O2 > H2O
- Common forms of Combustion
- Pipe Bomb
- Similar to GF
- Expel Shrapnel
- Car Engine
- Short, multiple combustions
- A Fire
- Explosion or spark
- A Gun Firing
- Powder meets detonator
- Small explosive propels bullet
- Pipe Bomb
- Equations
- What is fire?
- 4. Collecting & Analysing Explosives
- Criminal act or not?
- C & A an explosive that is intact:
- Device still in tact, fire = arson
- Fire caused by a similar explosive device
- 1. Make sure the ED is no longer dangerous
- 2. Check for explosive residue
- 3. DNA evidence
- 4. ED cross-referenced to a database of ET
- 5. Isolate materials & look for clues
- 6. Type of device used
- 5. Isolate materials & look for clues
- 4. ED cross-referenced to a database of ET
- 3. DNA evidence
- 2. Check for explosive residue
- 1. Make sure the ED is no longer dangerous
- Fire caused by a similar explosive device
- Device still in tact, fire = arson
- After an explosion
- No device left in tact, I must collect & analyse evidence from the scene to determine why the explosion has occurred and what materials helped
- Document condition of the scene
- Find evidence of the device
- Residue usually left over
- Ion mobility spectrometers
- Security Cameras?
- Switches
- Wiring
- Timers
- Residue usually left over
- Find evidence of the device
- Document condition of the scene
- No device left in tact, I must collect & analyse evidence from the scene to determine why the explosion has occurred and what materials helped
- 3. Types of Explosions
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