Let's say that there's a joint mission to the International Space Station, composed of American and British astronauts.
They get along well for the first few days, but tensions grow, and eventually an American crew member kills a one of the British group.
How would the investigation and trial be conducted? Who would investigate? What court would the defendant be tried in?
Is there some kind of "space rulebook" that spells out what to do with murder, or crime in general?