I really think he was captured---and died in custody. I don't think we (US) wanted to let the news out- out of concern for jihadi reaction. Again- the jihadi's knew that he was missing some time ago- they just did not know his fate. All they said was that he would not be returning to them- along with one other bozo.
OPINION-SPECULATION: The jihadis know what is up (or down) pardon the pun with UBL. They have graphics of him floating on top of clouds, in the clouds, and a graphic I saw recently (resembling a tombstone or grave marker) where he is in the middle and is surrounded by a dead jihadi on either side.
UBL IS DEAD, captured or in a hidey-hole. His evil spirit lives on via jihad.