Photographs are critical to documenting evidence and should be taken both at the fire scene and the recovery site. Questions to ask local authorities include:

• Were local investigators called?
• If so, what documentation is available?
• Was evidence recovered from the scene?
• Was the vehicle reported stolen?
• Was there fuel spillage?
• Were absorbent pads used and if so, what happened to them?

At the scene, look for items that might be missing from the vehicle. A lack of aftermarket equipment, tires in poor condition, missing electronic components and personal items could be an indication of arson. More than one set of tire tracks could be an indication of a second (getaway) vehicle. Also look for fuel cans nearby or in the vehicle and jack marks on the car.

It's easy for fire scenes to become contaminated, whether it's the fire company responding or the wrecker who takes the vehicle to a storage facility, there will be other footprints and tire tracks. Sometimes the wreckers will throw any trash and debris on site into the vehicle, contaminating the interior. Fire evidence is very fragile and easily contaminated. If possible, request that they put anything found on the flatbed next to the car instead of inside it.

Most arsonists assume that everything will go up in flames in the vehicle. In reality, there are often layers of evidence left after a fire. A trained investigator knows where to look and what to look for inside a vehicle.

Weather and time can destroy some of the evidence, but it is still possible to identify burn patterns. Whether or not a vehicle was sitting on a level surface will impact the burn patterns. Look at the windows and door trim to see which way the fire traveled. Is one side of the car severely burned and the other relatively untouched? Did one side of the interior burn more than the other? Are the windshield and dashboard area burned? Were the windows up or down?

Engine fires frequently have a circularized pattern and there will be burning in the engine compartment. Investigators should have a working knowledge of the operating systems in a car in order to rule them out as a possible cause of the fire. They should also be aware of any vehicle recalls in case they contributed to the fire.

A fire that started in a fuel tank may have a “V” pattern around the fuel door. This is caused by vapors venting from the fuel tank. The “V” may start at the top of the filler neck. They may also be seen above the wheel wells due to burning tires.

Many owners collect documents, food wrappers and other debris in their vehicles. If a fire was started intentionally and newspaper was used to help ignite it, it's possible to recover enough of the paper to find an actual date. Some claimants will say their cars were stolen and that they still have the keys. Check the ignition to see if the keys are there, have fallen on the floor and if the car is in drive or park. If the car was stolen, there should be damage to the D-ring and wafers for the ignition.

The next page shows several videos demonstrating how a car can be set on fire and the amount of time passing from ignition to being fully engulfed.

Here the ignition source for the fire has just been lit. The car smolders for a few minutes before flames can be seen.

Within a matter of moments, flames appear on the interior of the car.

In approximately 8 minutes, this car went from smoldering to being fully engulfed.

It took firefighters just moments to put out the fire.

A burned vehicle interior can yield a number of clues to a trained investigator. This vehicle was burned two days earlier than the car in the previous slide. Can you tell where the fire started and how it spread?