Judges 20:36-39

36Then the Benjamites saw that they were beaten. Now the men of Israel had given way before Benjamin, because they relied on the ambush they had set near Gibeah. 37Those who had been in ambush made a sudden dash into Gibeah, spread out and put the whole city to the sword. 38The Israelites had arranged with the ambush that they should send up a great cloud of smoke from the city, 39and then the Israelites would counterattack. The Benjamites had begun to inflict casualties on the Israelites (about thirty), and they said, “We are defeating them as in the first battle.”