Knowledge test Flashcards
What role does fire investigator play?
By accurately and efficiently identifying causes
Whether accidental or non-accidental
Real & substantial contribution to reducing losses
When was flammability of clothing & bedding identified?
1960s
Introduction of cigarette & flame resistant furniture
1990s
Only way to be sure regulation is having desired effect
Document effects of fire in regulation compliant buildings & transport
When to establish if arson has been committed
Every fire scene must be considered possible crime scene until clear proof accidental
Sherlock Holmes quote
“It is a capital mistake to theorise before one has data. One begins to twist facts to suit theories instead of theories to suit facts”
Investigator’s prime concern
Cause, not extent of destruction
Special need for every investigator to…
…develop a comprehensive analytical approach
To be successful fire investigator must understand and master facets of:
Fires
Fuels
People
Investigative procedures
Investigator must really understand:
How a fire burns
What factors control behaviour
That all fires do not necessarily behave in a precisely predictable fashion
Deviations from predictable behaviour of fire must be:
Correlated with fire conditions
Causes established
Causes of unpredictable fire
Nature of fuel
Physical circumstances & environment of fire
Properties of fuels
Density
Thermal conductivity
Heat capacity
Properties of fuels will
Determine ignitability
Determine flame spread characteristics
These control nature of ignition and following events
Ignition sources
Glowing
Flaming
Electric arc
Scientific method
Define problem > Collect data > Analyse data > Develop hypothesis > Test hypotheses
Repeat until:
Select final hypothesis
What is the scientific method?
Way to explain to others findings and logical analysis of information collected at the scene.
Explains your deductive reasoning.
Locard’s principle
When two objects come into contact there is an exchange of material
Police evidence
Finger marks Shoe marks Instrument/tooling marks Glass samples DNA Body tissue Physical fits/manufacturing marks Preservation
Finger marks - visual
Blood
Oil
Grease
Paint
Can be photographed
Finger marks - latent
Found with powders
Can be lifted with tape
Finger marks - surfaces
Glass Painted/varnished wood Plastics Paper Smooth leather
Shoe marks
Various surfaces Can be enhanced with powder Can be lifted with adhesive gel Can be photographed Casts from soil or sand
Instrument/tooling marks
Sample item/tool
Can take cast of tooling mark