Mission: Impossible - Season 6 Episode 16 : Stone Pillow (aka Big House) 1973

A private detective, Edison, has pictures incriminating Syndicate boss Vochek in a murder and is using them to blackmail the mobster. The IMF need to get the pictures to get Vochek convicted, but Edison has been convicted and is in prison for six months. Since Edison is unaware that his accomplice Leona is dead, Casey takes her role while Jim is Edison's cellmate and helps him to escape, then fake their deaths. Casey-as-Leona tells Edison she sent the evidence to the D.A. after she heard Edison was dead, and Jim convinces Edison she is keeping the pictures to pull off her own blackmail scheme. When Edison confronts her, Jim fake-shoots her but she calls a confederate to get the film - desperate, Edison reveals the location himself as he goes for it, and ends up arrested.