He was Chinese, not Japanese.
Answer :
U.S. Army Air Corp, - Captain, Military Intelligence.
IMBdYung served in the U.S. Army Air Forces during World War II, first making training films at the First Motion Picture Unit, then as a member of the cast of "Winged Victory," the Air Forces' theatrical play and film (as Sgt. Victor Young). He then requested officer training and apparently reached the rank of captain.
WikipediaIn 1972, a Pacific Southwest Airlines plane on which Yung was a passenger was hjiacked. The FBI stormed the plane, and in the ensuing gunfire Sen Yung was shot in the back. He and another wounded passenger survived, but a third passenger and the two hijackers died.
I think the original group was the Cowsills (whom the show was based on). I'm guessing that they didn't like the storylines that were being presented.