I'm sure some investigations work on that principle. They can't find the proverbial smoking gun (or burnt match in the bed perhaps would be a better term!) so the cause must be electrical, right? [Linked Image]

Maybe offtopic, but what can you do when you see something very dangerous?
In England, the answer is "Not much."

You can tell the home-owner, and that's about it. There are no electrical inspectors to report anything to. Power companies have a clause to the effect that they reserve the right to disconnect service to premises where the wiring constitutes imminent danger, but that would be extremely rare. These days most of them take the attitude that if it's on the owner's side of the meter, they don't care anyway.

Ultimately local councils have the power to condemn a building as unfit for human habitation, but such actions are also very unusual and are generally only ever implemented due to imminent structural collapse or something like a place being absolutely infested with rats.

I suppose someone might be able to convince the local council that a place be declared unfit for habitation due to extremely dangerous wiring, but I've never heard of such a case.

Councils ("City Hall") here have never had any interest in wiring whatsoever, although that's set to change next January (see the "part P" threads in the non-U.S. area).