Judges 20:37-40

The ambush erupted and made quick work of Gibeah. The ambush spread out and massacred the city. The strategy for the main body of the ambush was that they send up a smoke signal from the city. Then the men of Israel would turn in battle. When that happened, Benjamin had killed about thirty Israelites and thought they were on their way to victory, yelling out, “They’re on the run, just as in the first battle!” But then the signal went up from the city—a huge column of smoke. When the Benjaminites looked back, there it was, the whole city going up in smoke.