Judges 20:38-40

38Now the appointed signal between the men of Israel and the men in ambush was that they would make a great cloud of smoke rise from the city.

39So the men of Israel turned in the battle, and Benjamin began to strike and kill about thirty men of Israel, for they said, “Certainly they are defeated before us as in the first battle!”

40But when the [signal] cloud began to rise out of the city in a column of smoke, the Benjamites looked behind them; and behold, the entire city went up in smoke to heaven.