While I admittedly don't know much about this myself, I would imagine that Xander in this story would be tried under military law. I don't know how this would affect your story though since a quick search on the internet tells me that military prisoners can be held in normal prisons. I would do more research since it didn't say anything about people who are given the death sentence.
I like your idea, but I think it might work better as an original story.