Based on real crimes that occurred in Snowtown, Australia, in the late 1990s, The Snowtown Murders is a dull thriller of ultra-bleak withholding. Elizabeth (Louise Harris) goes out and leaves her three sons with a male neighbor who coaxes the boys into a nude photo shoot. With the help of a boozy neighborhood group that gathers to vent rage against what is apparently a local epidemic of pedophilia, the family runs the neighbor out of town. Mom then takes up with the group’s leader, John (Daniel Henshall), who forms a bond with pretty-boy son Jamie (Lucas Pittaway). “You like getting fucked?” John asks Jamie. When the teenage boy answers in the negative, John inducts him in his master plan (visualized through—what else?—one of those bedroom-wall schematics of photos, addresses, and cartoons of men getting stabbed) to eradicate the town of all suspected “pervs.” Jamie, of course, thinks he’s doing good by abetting this self-appointed moral vigilante. He’s not. Director Justin Kurzel’s m.o. seems to be to leave the audience in the dark regarding the depths of evil in Snowtown for as long as possible, but thanks to “naturalistic” performances and the fact that half the dialogue scenes seem to take place over meals, with thickly accented actors mumbling around the food in their mouths, he keeps basic character and narrative information mysterious, too. The climate of confusion might be a way of making tangible Jamie’s mental state, which is casually revealed late in the game to be clinically awry. But this slog adds up to nothing other than the shocking truism that average people will do horrible things primarily because someone tells them to.