Exodus 21:13

But if he did not lie in wait for him, but God let him fall into his hand , then I will appoint for you a place to which he may flee .

However, if it is not done intentionally, but God lets it happen, they are to flee to a place I will designate.

And if a man lie not in wait, but God deliver him into his hand; then I will appoint thee a place whither he shall flee.