The trailer for Pushover.
An honest cop Paul Sheridan (Fred MacMurray) is tasked to track down over $200,000 in the hands of a gangster after a bank robbery. The cop maintains a 24-hour surveillance on Lona McLane (Kim Novak) - a girlfriend of one of the robbers.
The cop quickly falls in love with Lona, who, when she finds out he's a policeman, tries to persuade him to kill Harry Wheeler (Paul Richards) so the two can take off with the cash. He initially resists, but eventually agrees.
But after the killing, he finds that he also has to kill his detective partner Paddy Dolan too, in order to cover his tracks. Almost all the action takes place, at night, in the U-shaped apartment building where Lona lives.