The story was based, in part, on the mysterious death of martial arts legend Bruce Lee. Lee died under mysterious circumstances a few years earlier.
Harold Sakata's dialog seems to have been dubbed by actor James Hong, but no credit was mentioned.
One of the writers/contributors is Joe Hyams.
Hyams wrote the book, "Zen in the Martial Arts" and was also a long-time student of the martial arts and trained with Ed Parker and Chuck Norris.