City of Oswego Fire Department

Arson Awareness

Fire Scene Preservation

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

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

Fire Behavior

Normal Fire Patterns One ignition source Growth is upward and outward ‘V’ patterns form

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

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

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

Environmental Observations

Wind direction and speed Weather conditions Neighborhood conditions

Real estate values For sale signs Problem areas

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

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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

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

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

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

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

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

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

Observations at the Scene

Incendiary devices: Trailers Fusees Match books Hypergolic chemical mixtures

City of Oswego Fire Department

City of Oswego Fire Department

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

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

‘V’ Patttern

City of Oswego Fire Department

Origin and Cause often found at apex of ‘V’

City of Oswego Fire Department

Area of Origin

City of Oswego Fire Department

Point of Origin/

Source of Ignition

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Line of Demarcation

City of Oswego Fire Department

Clean Burn

City of Oswego Fire Department

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

City of Oswego Fire Department

City of Oswego Fire Department

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

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

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

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

Preserving Evidence

NEVER move or dismantle evidence. Destruction of context Spoliation