Don't Bother to Knock (1952)

Synopsis
Sex symbol Marilyn Monroe went dramatic in 1952's Don't Bother to Knock. Monroe plays Nell Forbes, a beautiful but suicidal young woman, recently released from a mental institution. She doesn't mention this on her resumé when she takes a baby-sitting job in a posh hotel. Jed Towers (Richard Widmark), a hotel guest, tries to make time with Nell after his own girlfriend, played by Anne Bancroft, has told him to take a hike. As Nell and Jed neck on the couch, the little girl whom Nell is tending (Donna Corcoran) surprises the spooning couple. This drives the psychotic Nell over the edge, forcing Jed to try to keep the baby-sitter from killing both herself and the child. ~ Hal Erickson, All Movie Guide