The basic theory of US law here is that members of the military who are alleged to have committed offenses while in uniform and performing military duties are liable only to military law. Civilians courts, including coroner's courts, have no jurisdiction. It is entirely different when an offense is committed off-duty, especially if it is in a location, such as the Japanese possession of Okinawa, where there is a "Status of Forces Agreement" in place. There, members of the US military are subject to arrest by Japanese police and trial in Japanese courts.