Murder!

Murder! is a movie starring Herbert Marshall, Norah Baring, and Phyllis Konstam. A juror in a murder trial, after voting to convict, has second thoughts and begins to investigate on his own before the execution.
When a woman is convicted of murder, one of the jurors selected to serve on the murder-trial jury believes the accused, an aspiring actress, is innocent of the crime and takes it upon himself to apprehend the real killer.