Judges 20:38-40

38The men of Israel had a prearranged signal with the men in ambush: when they sent up a great cloud of smoke from the city,

39the men of Israel would return to the battle. When Benjamin had begun to strike them down, killing about thirty men of Israel, they said, “They’re defeated before us, just as they were in the first battle.”

40But when the column of smoke began to go up from the city, Benjamin looked behind them, and the whole city was going up in smoke.