The Lady Takes The Stand is the 32nd in the Turn Of Fate television short movies and is from 1958 (bottom left image).
Jane Powell plays Marian and Keith Andes plays David Cramer.
Cramer’s wife is murdered by an intruder and he’s suspected, charged, found guilty and imprisoned.
Marian is his lover, as well as his wife’s nurse, and she sets about tracking down the real killer.
She does and the police arrive just in time to make the arrest before he kills the couple.
Movie pages here.