We read that Achan confessed his sin of taking spoil that was proscribed for the Lord:
Achan answered Joshua, “It is true, I have sinned against the Lord, the God of Israel. This is what I did: I saw among the spoil a fine Shinar mantle, two hundred shekels of silver, and a wedge of gold weighing fifty shekels, and I coveted them and took them. They are buried in the ground in my tent, with the silver under it.”—Joshua 7:20-21 (NJPS)
But when it was time to punish the sin, Achan's children were included:
Then Joshua, and all Israel with him, took Achan son of Zerah—and the silver, the mantle, and the wedge of gold—his sons and daughters, and his ox, his ass, and his flock, and his tent, and all his belongings, and brought them up to the Valley of Achor. And Joshua said, “What calamity you have brought upon us! The Lord will bring calamity upon you this day.” And all Israel pelted him with stones. They put them to the fire and stoned them.—Joshua 7:24-25 (NJPS)
This seemed to mollify God's anger.
Why then were Achan's children destroyed? Was it because Achan's sin was transferred to his children, or because his children were considered his property and not separate individuals, or because they were complicit in the sin, or for some other reason?