Joshua 8:24, 28-29

And it came to pass when Israel had made an end of slaying all the inhabitants of Ai in the field, in the wilderness where they pursued them, and when they all had fallen by the edge of the sword until they were consumed, that all the Israelites returned to Ai and struck it with the edge of the sword.

So Joshua burned Ai and made it a heap forever, a desolation to this day. And the king of Ai he hanged on a tree until evening. And as soon as the sun was down, Joshua commanded that they should take his corpse down from the tree, cast it at the entrance of the gate of the city, and raise over it a great heap of stones that remains to this day.