Lassiter (also known as The Magnificent Thief) is a 1984 American heist spy film starring Tom Selleck and Jane Seymour.

connection is perhaps most clearly seen by the movie poster tagline: The Magnum Man Hits the Big Screen with a Vengeance.

He is arrested by the police after breaking into a London mansion and, after being a member of a phony lineup in which he is positively identified by a law enforcement plant, British law enforcement and the FBI blackmail Lassiter to break into the German Embassy and steal $10 million in Nazi diamonds from a German spy (Lauren Hutton), but first he must locate their hiding place.

The gems are en route to South America and will be sold to help finance Hitler's military buildup.

The authorities want the Nazi diamonds and to put Lassiter away for good, but he has other plans, and a surprise twist ending changes everything.