Preserving a Fire Scene Flashcards
Guarding and controlling the scene
List the scene security considerations for Police
- Making sure the scene is not interfered with
- Making sure bystanders/property owners/and others are excluded from scene
- Potential evidence is preserved
- Prevent looting
- Aware of potential hot spots and re-ignition
- Aware of possible suspects at scenes
- Aware of possible witnesses
- Report all significant matters to O/C and Scene co-coordinator
Fire Scene contamination
To assist in scene preservation, what points do you need to consider and describe each point
SCOPE - How much of the area needs to be preserved?
* single room
* entire building
* a large area that includes a building or buildings
* outside areas.
Apply the investigation process as described in this document, and make an informed decision as to where most of the information you require is located, and what needs to be preserved.
* CORDON - dentify the centre of the scene
* tape off outside, what is considered to be the most obvious item of evidence that is furthest away from the centre of the scene (see ‘Explosives examination’).
* In large scenes the natural boundaries could be used to dictate your zones.
COMMON APPROACH PATH - All traffic through the scene should be limited to ‘corridors’, i.e. the paths which will keep disturbance of the scene to a minimum.
Ideally, the investigator should search the areas to be used as corridors prior to them receiving any other traffic. This will reduce the possibility of ‘evidence’ being introduced to the scene after the event. It will also reduce the possibility of evidence being damaged during subsequent fire inspections and investigation.
WHEN IT IS DIFFICULT TO PRESERVE THE SCENE - In certain circumstances, such as demolition of specific areas due to safety, it may be difficult to preserve the scene. In cases such as this the investigator must record the scene, prior to demolition, by:
* sketches
* photographs
* plans
* video recordings.
This will assist in recalling the layout of the premises prior to demolition work being carried out. Some steps can be taken as shown below in examining the scene without disturbing it or endangering staff.
Personnel
A specialist Fire Investigator should be present at all fire scenes Police are required to attend. List who you may also need the assistance from
- fire investigation liaison officer
- ESR scientist
- rural fire investigator
- photographer
- fingerprint technician
- explosives inspector
- electrical inspector
- building inspector
- insurance assessor
- accountant
- forensic mapper/original floor plans
- pathologist
- vehicle inspector
- civil aviation inspector
- mines inspector
- forestry expert
- agricultural expert
- marine surveyor
- heating engineer
- meteorologist.
What should the OC Investigation do once all required personnel have been identified?
- appoint an exhibits officer
- appoint a crime scene co-ordinator (if required)
- advise the Fire Investigation Liaison Officer
- appoint a scene examiner
Preparing the Examination
List steps you would take when preparing for an examination
- Arrange for the scene to be examined as soon as possible
- Scene should be examined systematically from the outside in
- Establish a clear area for material removed during search
- Avoid cross contamination potential
What is the point of origin?
The point of origin is the exact location at which
- A component failed
- A fire was maliciously lit
- An accidental fire originated
External Examination
What does the external examination take into account?
- Accelerant containers
- Attempts at forced entry
- Broken windows
- Forced doors
- Nearby alleyways/streets/driveways
- The yards and outbuildings of the fire effected property
- The periphery of the structure itself
- What distance debris was scattered, particularly if drums or cylinder have exploded
The surrounding area of the involved premises may also reveal, what?
- Accelerant containers
- Contents of outbuildings missing
- Property run-down
- Business appears to be struggling
The damaged structure itself may reveal, what?
- Jemmy marks or other signs of forced entry on windows or doors
- Window glass broken before the fire was ignited
- Burn patterns above doors and windows and “V” shaped burn patterns on external cladding
Preliminary internal examination
When doing a internal preliminary examination form the area of least damage to most damage, what indicators should you be looking?
- low stock levels in commercial premises
- building areas in need of repair
- signs of hardship (empty flats, shops to let, etc.)
- missing family photographs, furniture and personal items
- lack of clothing in wardrobes and drawers
- rifled premises
- position of clothes if not in wardrobe or drawer
- open filing cabinets or missing files
- forced entry into an empty till
- presence of accelerant containers or trails
- separate unrelated seats of fire
- owner/occupier attitude during walk through (if access is permitted)
- unusual odours
- burn patterns.
Detailed Internal Examination
When conducting a detailed Internal Examination with the SFI, what observations would they be looking for?
- smoke deposits and burn patterns
- spalling (the cracking or chipping of concrete as a result of being heated and cooled)
- damage to wall studs
- damage to roofing timbers
- damage to windows sills and door edges
- soot deposits on window glass and craze patterns
- floor areas burned through
- skirting board damage
- elimination of false low burns
- removal of fire debris, and
- under floor inspection.
At the conclusion of detailed internal examination, what will the SFI be able to determine?
- Area of origin
- Point of orgin
- The seat of the fire
In determining the seat of the fire the SFI will consider what?
- witness’ reports
- when they first noticed the fire, and where they were at the time
- the state of the fire at that time
- wind direction and speed, and the weather
- the direction of spread
- the colour of the flames and smoke (this may also point to the cause; for example, black smoke may indicate a petroleum product based fire)
- the severity of the damage (because fire and heat usually rise, the area at the lowest level of burning with the most severe damage is often the place where the fire started. Remember that lateral and downward burning can occur with some materials and in the presence of accelerants or draughts)
- the depth of charring (probing may indicate where the fire has been burning or smouldering the longest)
- the presence of ‘starting devices’
- the reports and opinions of other specialists.
The cause of the fire
List types of evidence regarding a Molotov Cocktail
- olystyrene beads.
- Rubber bands.
- Soap flakes. These are dissolved into the warmed petrol, producing a mixture that sticks to anything it touches. Soap also slows down the burning rate of petrol while allowing it to produce the same heat.
- Soap powder, sugar or flour. These slow down the petrol’s burning rate and confine its spread, providing better heat at the target area.
- Materials that ignite on impact, eliminating the need for a wick. The container is filled with a mixture of petrol and 10 to 15 percent concentrated sulphuric acid. A small sachet containing a 50/50 mixture of potassium chlorate and sugar is taped to the outside of the bottle. Once the bottle breaks, the acid reacts with the potassium chlorate/sugar mixture and ignites.
- Traces of wick, often in the broken neck of a bottle.
- Pieces of bottle glass, either scattered or in one place. If the bottle does not break on impact, it will fall apart with the heat as the cocktail burns, and be found at the seat of the fire.
- Pieces of window glass from the cocktail’s entry.
- In the case of chemical ignition, traces of the tape used to attach the chemicals to the side of the bottle; or the type of burn characteristic of sulphuric acid. This burn can be identified by chemical analysis.
- Evidence of liquid flowing down walls, and under doors and furniture.
- Evidence of rubber bands, egg white residue, gelatine or similar substances stuck to flooring or walls
List types of evidence regarding a timing device
- A bottle containing the acid is suspended above the dry ingredients and tipped by a length of cotton attached at the other end to the alarm winder of a clock.
- The acid is placed on a balance with a tin of water at the other end. A tiny hole is punched in the tin and as the water drips away, the balance tips and drops the acid into the dry ingredients below.
- Most common is the use of an incense stick or matches cut to length to determine the timings required.
- Electric timers can be used to delay the start of a fire long enough to allow an arsonist time to be well away from the scene. A recovered timer may show when it was set.
