In the morning therefore you shall be brought near by your tribes: and it shall be, that the tribe which Yahweh takes shall come near by families; and the family which Yahweh shall take shall come near by households; and the household which Yahweh shall take shall come near man by man.
Israel resorted to the casting of lots when no eyewitness could testify against a criminal (cf. 1 Samuel 14:41-42; Jonah 1:7; Proverbs 18:18). Probably the high priest used the Urim and Thummim to identify Achan (cf. Numbers 27:21).