The Split (1968)

A man named McClain's tasked with planning the robbery of a Los Angeles Coliseum after a big game. He recruits 4 men. The job goes off without a hitch. When they ponder where to keep the money McClain suggests they leave it with Ellie, his girlfriend. But when she's killed, the money's vanished, and they all wonders what happened. They assume McClain knows where the money is, but he doesn't. He thinks the cop investigating the robbery and Ellie's death know more than he's letting on.