Hung is the past tense and past participle of hang in most of that verbs senses. For instance, yesterday you might have hung a picture on the wall, hung a right turn, and hung your head in sorrow. The exception comes where hang means to put to death by hanging. The past tense and past participle of hang in this sense, and only in this sense, is hanged.
http://grammarist.com/usage/hanged-hung/
Great. Then he should still be hanged first and then face a trial!