1. Fire Scene Preservation
Arson Awareness
Fire Scene Preservation
City of Oswego Fire Department

2. City of Oswego Fire Department
Objectives
Identify and describe the importance of observations made prior to, during or after a fire
Describe the importance of preserving a fire scene for cause determination.
Describe methods of preserving fire scene evidence.
City of Oswego Fire Department

3. City of Oswego Fire Department
Fire Behavior
Fire behavior is predictable.
A normal fire follows a predictable path of fire progression.
Growth Stage
Free Burning
Decay
City of Oswego Fire Department

4. City of Oswego Fire Department
Fire Behavior
Normal Fire Patterns
One ignition source
Growth is upward and outward
‘V’ patterns form
City of Oswego Fire Department

5. City of Oswego Fire Department
Fire Behavior
Abnormal fire growth or burn patterns may indicate non-accidental cause:
Unusually heavy destruction in area of origin.
Inverted ‘V’ patterns
Multiple areas of origin.
City of Oswego Fire Department

6. City of Oswego Fire Department
Observation Skills
Cause determination is based on various types of evidence.
Burn patterns
Point of origin
Elimination of causes
Witness interviews
Occupants
Bystanders
Firefighters
City of Oswego Fire Department

7. City of Oswego Fire Department
Observation Skills
Firefighters are primary witnesses to the event, before, during and after the incident
Their observations can assist the efforts of investigators immensely.
Firefighters should be prepared to provide written witness statements after the fire.
Their ability to preserve evidence for investigators is crucial to cause determination.
City of Oswego Fire Department

8. Environmental Observations
Wind direction and speed
Weather conditions
Neighborhood conditions
Real estate values
For sale signs
Problem areas
City of Oswego Fire Department

9. City of Oswego Fire Department
Observations Enroute
Note fire conditions reported from dispatch.
Vehicles or people leaving the scene
Normally people move toward the fire
Unusual circumstances or obstacles
Blocked access
City of Oswego Fire Department

10. Observations at the Scene
Note time and fire conditions on arrival
Occupants clothing
Occupants behavior
Over curious
Indifferent
Too helpful
Bystanders (familiar faces?)
Location of fire
City of Oswego Fire Department

11. Observations at the Scene
Smoke color
May indicate what is burning.
May indicate the stage of the fire
Fire travel
Unusual signs or routes of fire extension.
Rate of Combustion
City of Oswego Fire Department

12. Observations at the Scene
Exterior evidence
Tracks
Flammable liquid containers
Greatest damage may help locate area of origin
Area of origin
Follow damage from least burned area to the area of greatest damage.
Is ignition source readily identifiable?
City of Oswego Fire Department

13. Observations at the Scene
Means of Entry
Were doors locked or unlocked?
Signs of force entry prior to arrival.
Condition of Windows
Open or closed.
Shades up or down
Broken
Is the glass inside or out
Smoke stained or not
City of Oswego Fire Department

14. Observations at the Scene
Unusual odors
Petroleum or solvents
May prompt the taking of samples
Any containers on site, inside or out?
Difficulty of extinguishment
Did fire react normally when water was applied
Did fire reignite or flash back
City of Oswego Fire Department

15. Observations at the Scene
Room Arrangement
Furnishings in place or absent
Correct items in the room
Do items appear to be substitutes?
Signs of burglary
Are valuables missing
What’s burning?
Can object be identified.
If not, eliminate other causes
City of Oswego Fire Department

16. Observations on Arrival
Signs of fire spread by unusual methods:
Trailers
Out of place fuel sources.
Splash or pour patterns
Inverted ‘V’ or cone patterns
Did fire protection work?
Detection systems
Suppression systems
Did system control fire? If not, why not?
City of Oswego Fire Department

17. Observations at the Scene
Incendiary devices:
Trailers
Fusees
Match books
Hypergolic chemical mixtures
City of Oswego Fire Department

18. City of Oswego Fire Department

19. Observations on Arrival
Depth of charring
Depends on type of wood and length of burn
May help indicate area of orign
May help determine length of time fire burned
Spalling
Annealing of springs
Beading on wiring
City of Oswego Fire Department

20. Observations on Arrival
Burn Patterns:
‘V’
Inverted ‘V’
Truncated cone
Hour glass
Lines of demarcation
Clean burn
Staining of glass
City of Oswego Fire Department

21. City of Oswego Fire Department
‘V’ Patttern
City of Oswego Fire Department

22. City of Oswego Fire Department
Origin and Cause often found at apex of ‘V’
City of Oswego Fire Department

23. City of Oswego Fire Department
Area of Origin
City of Oswego Fire Department

24. City of Oswego Fire Department
Point of Origin/
Source of Ignition
City of Oswego Fire Department

25. City of Oswego Fire Department
Line of Demarcation
City of Oswego Fire Department

26. City of Oswego Fire Department
Clean Burn
City of Oswego Fire Department

27. Observations on Arrival
Separate fires
May be caused by dropdown
May be evidence of set
Means of Entry
Doors locked or unlocked
Signs of forced entry prior to arrival
City of Oswego Fire Department

28. City of Oswego Fire Department

29. City of Oswego Fire Department

30. Observations on Arrival
Indicators of the direction of fire spread
There may be more than one ‘V’ pattern
Look for lowest burn
Melted glass and light bulbs.
Different degrees of charring on furnishings
City of Oswego Fire Department

31. City of Oswego Fire Department
Preserving Evidence
The entire fire scene is of evidentiary value, not just the apparent area of origin.
Overhaul is a destructive, but necessary phase of fire suppression.
Opening voids to check for extension.
Pulling appliances away from walls
Opening furniture cushions, bedding and mattress to eliminate deep seated fire.
All of these activities may destroy evidence.
City of Oswego Fire Department

32. City of Oswego Fire Department
Preserving Evidence
When conducting overhaul, be able to recognize evidence which may be of use to investigators.
Delay overhaul, if possible, until a fire investigator can assess the scene.
If overhaul cannot be delayed, attempt to keep damage to a minimum, and report observations to investigator ASAP.
City of Oswego Fire Department

33. City of Oswego Fire Department
Preserving Evidence
Attempt to preserve fire patterns and other physical evidence during overhaul.
Inspection holes
Leave furniture in place or return to original position.
Minimize water damage.
Limit number of personnel in area.
City of Oswego Fire Department

34. City of Oswego Fire Department
Preserving Evidence
NEVER move or dismantle evidence.
Destruction of context
Spoliation
City of Oswego Fire Department