Where should this case be tried?

Global Military Justice Reform regularly asks the above question -- we should call it Question No. 1 -- where criminal conduct by military personnel may straddle the military/civilian line. Here's one from Ghana. The facts of the case are essentially these: a 16-year-old civilian steals a cellphone from a soldier. The owner of the phone and two other soldiers proceed to beat up the thief to the extent that he requires medical attention. Presumably both the theft and the assault occur off base. Civilian law enforcement -- the Ghana Police Service -- are on the case, although the soldiers remain in the guard room.

Should the case wind up in civilian court or a court-martial (or other military disciplinary action)? Comments welcome (real names only, please).