Ronald Colman won an Oscar for the lead role in the 1948 film A Double Life, in which he plays Broadway star Anthony John, a disturbed man who kills Shelley Winters, a waitress he picks up in a coffee shop. He later almost takes the role of Othello too far and comes close to strangling his costar on stage.
Pick any gangster movie. All the Godfather movies, Scarface, etc.
If they just organize the murder do you still count it?
To be fair, in The Godfather, Micheal Corleone did shoot the Turk and Captain McCluskey (in the restaurant, with the revolver)
Oh, that reminds me!
The dashing lead played by Montgomery Clift in A Place in the Sun (1951) does a Scott Peterson number on Shelley Winters - not that she was “the bad guy” in any meaningful sense apart from being dreadfully whiny and annoying and really unforgivably frumpy when contrasted with Elizabeth Taylor.
Remember: If you want your audience to retain some sympathy for a protagonist that’s going to commit murder, be sure to cast Shelley Winters as the victim - she’s your girl! (She got the Oscar for this one. Deserved it, too! I would have held her under.)
Shelley was nominated for Best Supporting Actress for A Place in the Sun, but didn’t win. Her first Oscar didn’t come till 1959, for The Diary of Anne Frank, and her second in 1965 for A Patch of Blue. She suffered another watery death and Oscar nomination in 1972 in The Poseidon Adventure. And the movie version of A Place in the Sun leaves it somewhat ambiguous about the drowning – Clift’s character plans to kill her, but apparently changes his mind – when at the last minute she stands up in the boat. Idiot.
In Hunt for Red October, Sean Connery’s character (Ramius) kills the political officer on board in pretty cold blood.