Showdown in Little Tokyo - Mark L. Lester

Detective Chris Kenner was orphaned as a child as his father was in the service and was killed and lived in Japan. Now he is on the trail of ruthless Yakuza leader named Yoshido, who helped establish a small Japanese area in Los Angeles and is now running a drug ring disguised as a brewery. However, Kenner must team up with a Japanese-American detective named Johnny Murata, and he also must protect a witness named Minako who would testify against Yoshido. But what Kenner will soon discover that he will be in a lot more than what he bargained for.