Return of the Kickfighter (1987)

The plot concerns a unit of US marines operating in the Vietnam war during 1970, with the movie opening on a raid in a village. After massacring the villagers, the marines steal the villages gold, much to the objection of their Vietnamese translator and guide. Skip forward past the credits sequence; it's now 15 years later, and members of the unit are getting murdered one by one. This leads to the former head of the group, now a high ranking military officer, announcing that the only person who is up to the job of finding out the identity of the killer is an Aussie, Major Brad Cooper.

Unfortunately the movie Return of the Kickfighter is not yet available on HBO Max.