"Military Bases are regarded as U.S. soil." Not hardly. Most bases are subject to what is called a Status of Forces Agreement, which governs the legal status of military personnel. Some SOFAs also include military dependents and US citizens who are employed on base. Depending on the terms of the SOFA, these civilians may or may not be subject to local legal processes. In many cases, a civilian committing a crime on a military base is liable to prosecution according to the laws of the host nation; in others (and Japan is one) members of the military are subject to local law if they commit an offense against a local national, on base or not.