How do firemen know the cause of a fire after everything has burnt down?

Question

Often times you hear about the cause of a fire being a cigarette for example. However, isn’t the cigarette already long gone after the house/forrest/etc. has burnt down? How is it still possible find out what started the fire?

In: 567

Answer 1

its a very difficult question to know what exactly started the fire, its been burning since the worlds been turning