Judges 20:38-40

38Now there was a prearranged sign between the men of Israel and the men in ambush—they would make a great beacon of smoke rise up from the town—

39then the men of Israel would return to the battle. When Benjamin began to strike, killing about 30 of the men of Israel, they said, “Surely they are defeated before us, as in the first battle.”

40But when the beacon began to arise up from the town in a pillar of smoke, Benjamin looked behind them, and behold, the whole town was going up in smoke to the sky.