THE LOST TRIBE. 1983

An anthropologist vanished on a seemingly uninhabited island off the coast of New Zealand, where he had been investigating a site where a Mauri tribe was slaughtered generations before.

As this horror thriller unfolds we glimpse evidence of an unchanging primitive tribe of Mauri who have remained undiscovered due (it appears; the script never makes any of it clear) to dream-time magic.

Or they may only be ghosts or even a murderer's elaborate hoax. The film remains vague on all points & not half as good as the idea for it.