This Bible contradiction is from the Skeptic's Annotated Bible.
They should be killed
Leviticus 20:13 View context
If a man also lie with mankind, as he lieth with a woman, both of them have committed an abomination: they shall surely be put to death; their blood shall be upon them.
They should be exiled
1 Kings 15:11-12 View context
And Asa did that which was right in the eyes of the LORD, ... he took away the sodomites out of the land.