LOL.. yeah u do. 3.5 GALLONS of lighter fluid? Think to yourself what it does when you squirt it into a grill.. and that's probably an once or 2. Lighter fluid is very volitile. Now, hypothetically, if it was ALL put into the trunk?
If you were dumb enough to start it from the trunk closely (via a lighter) your ignorance would be severly punished. As a matter of fact, with 3.5 gallons of it you might as well jump in the trunk itself and light it.
If they used that,, it was all over the car, not centralized. If so, the torcher would either have to had left the trunk open and THROWN a fuse in, OR, they would be taking his confession from a burn unit.