The Last Wave (1977) on Netflix

In Sydney, Australian legal aide asks lawyer David Burton to assist on a case defending five urban aborigine men - Chris, Gerry, Jocko, Larry and Lindsey - charged with manslaughter of another urban aborigine, Billy Corman. They asked David, a corporate tax lawyer, solely because he is the one person they knew who had some, albeit little, experience dealing with aborigines in his work. The story is that during one of the latest in a series of violent and freak storms to hit Australia, the men got into a drunken fight outside a bar, Billy was knocked to the ground, and he died drowning in a pool of water. Not saying much, the men charged deny killing Billy, which David initially believes, but he also has a feeling that, through their silence, the men know who killed Billy. Reading between the lines of what the men say and reading about another case, David begins to believe that Billy's death may have actually been a tribal killing despite none of the accused or Billy being tribal men. The case takes on a new meaning when David meets Chris for the first time, he who is the mysterious figure in some of the nightmares that have kept David up even before this case began. As David continues to have somewhat cryptic discussions with Chris and another mysterious aborigine named Charlie, as David's nightmares continue, as he learns about incidents from his childhood from his stepfather, and as the storms become more unusual, David changes the focus of his thoughts from the case itself to what happened to Billy within the bigger picture and his own place within it all.