Joshua 8:27 (KJV)

And so it was, that all that fell that day, both of men and women, were twelve thousand, even all the men of Ai.

For Joshua drew not his hand back, wherewith he stretched out the spear, until he had utterly destroyed all the inhabitants of Ai.

Only the cattle and the spoil of that city Israel took for a prey unto themselves, according unto the word of the Lord which he commanded Joshua.

And Joshua burnt Ai, and made it an heap for ever, even a desolation unto this day.

And the king of Ai he hanged on a tree until eventide: and as soon as the sun was down, Joshua commanded that they should take his carcase down from the tree, and cast it at the entering of the gate of the city, and raise thereon a great heap of stones, that remaineth unto this day.