The Sister-in-Law (1974)

Robert and Edward are brothers involved in a web of adultery and deceit. They share Edward's wife and his mistress and a mission to deliver a package of jewels across the Canadian border, but the mission turns out to be deadly.

Directed by: Joseph Ruben

Starring: John Savage, Will MacMillan, Anne Saxon, Meridith Baer, Frank Adonis, Jonathan Oppenheim

Links: IMDb, Movie posters, Movie stills