What to Do About Ongwen?

The Washington Post has a fascinating article today about the legal issues arising from the surrender of one of the the notorious brutal leaders of the Lords Resistance Army, Dominic Ongwen.  Apparently he surrendered to Muslim rebels in the Central African Republic who, in turn, transferred custody of Ongwen to American forces on January 5.  He has been in our custody every since.  The question is what to do with him.  Our troops were there as advisors to the African Union who were searching for Joseph Kony, the leader of the LRA, but now they have involuntarily been thurst into an operational role. Since there are no US charges against Ongwen, continued detention seems unlikely.  He will be transferred to someone else -- but who?  Do we directly transfer him to the International Criminal Court (where he is facing charges, but whose treaty of creation we have never acceded to)?  Do we give him to the Ugandan authorities who may, or may not, want to try him for crimes against their citizens (he is alleged to have participated in genocide in Uganda)?  Do we give him to the  authorities in the Central African Republic (which is now riven by conflict itself and, effectively, cannot deal with his capture)?  Do we (as it appears we plan to) turn Ongwen over to the soldiers of the African Union whom we are there to support, knowing that they, in turn, will render Ongwen to the ICC?  And, as a bonus question -- since the US offered a $5 million reward for Ongwen, do we now give that bounty money to the Muslim rebels, to whom we are generally opposed and whom we have previously condemned?  (Our own John Bellinger earlier addressed the United States' issuance of a reward for Joseph Kony's transfer to the ICC, here.) I have no idea what the right legal answer is, nor what the right policy answer is.  As I said, fascinating ....