Murder Party (1961)

Directed by Helmut Ashley

Klaus murders women. After killing another girl, Klaus is spotted by his friend Kersten as he leaves his latest victim's house. Kersten gives him a ride and Klaus begins to plot the man's death. He's a witness, after all. Nobody else can say Klaus was there except Kersten. They decide to head to a party. Klaus' unhappy wife is there. So are a bunch of other people. Killing Kersten will be difficult. Then they all play a game called... Murder Party!