One Mysterious Night is a 1944 crime film, the seventh in a Columbia Pictures series of fourteen starring Chester Morris as reformed crook Boston Blackie.
Under intense pressure from the police commissioner to recover the diamond, Farraday tells reporters, among them Dorothy Anderson, that he is sure Boston Blackie is responsible.
When Blackie walks into Farraday's office, the inspector is so desperate he deputizes his old nemesis to get the jewel back, using his own methods.
Daley's sister Eileen finds out that her brother is involved with thieves Paul Martens and Matt Healy, and that he later hid the diamond in her purse.
Blackie tells his captors that what they have is a fake that he intended to switch with the real diamond, supposedly stored in a vault.
However, when the police surround the place, Martens and Healy realize they have been double crossed, and shoot Madigan, though not fatally.