How do investigators catch people who start fires?

Question

I often see in the news people getting arrested for started fires. What I want to know is how do the investigators catch these people? Obviously some might be stupid and get caught in the act or seen by witnesses. But most of the time this isn't the case. So when a person say dumps gasoline in a forest, lights a match, then runs away, how the heck do they prove or even find out who did it? Also consider the fact that any evidence like forensic hairs are probably burned away!

If the person doesn't leave anything behind (gas container), doesn't touch anything, and like I said the microscopic hairs are burned in the fire, I don't see how forensics could be used...

Answer 1

Even the most intense fire will usually leave behind sufficient clues that show what ignited it and whether or not it had a natural/accidental cause. For instance, it's easy to tell if a fire was started by an arsonist if he used gasoline as an accelerant. There will be trace aromatic hydrocarbons left behind which a forensics dog can smell. Proving who started a forest fire can be tricky if there are no witnesses and if the psycho doesn't brag about it after a few drinks at the local bar (don't laugh. A lot of undercover cops hang out at bars because a psychopath's worst enemy is often his own ego), but it's fairly easy to catch an arsonist who burns down a building. Once there are any traces of accelerants detected or no explainable accidental causes for the fire can be found (shorted wiring, corroded gas line, carelessly discarded cigarette, etc), all you have to do is find somebody with a motive and no alibi and it's usually easy going from there. You'll find it's typically either going to be the building owner looking to commit insurance fraud, or an enemy of his looking to do him in.

Answer 2

That's exactly why the vast majority of these cases go unsolved. It requires an enormous amount of luck/stupidity and piecing together seemingly unrelated clues. People that are caught usually are repeat offenders that finally screw up or arouse suspician in the interegation.

Answer 3

forensics, there is always forensic evidence, like fingerprints on the gas container. Or just piece by piece.

Answer 4

You must be a firebug for asking this and I have reported you to Homeland Security after taking a breather.

Answer 5

They can track records of who bought gasoline and the matches and all this crazy stuff; you'd be surprised.

Answer 6

Accidentally start a fire?

Answer 7

dna