Season synopsis
Contains spoilers for this season and earlier seasons.
Season 5 moves among show business, diplomacy, espionage and bullfighting. Former star Grace Wheeler kills her husband after he refuses to fund her stage comeback, and stages his death as suicide; Columbo’s investigation uncovers her degenerative illness, and her longtime partner Ned Diamond falsely confesses to protect her. At an embassy, diplomat Hassan Salah murders a security officer and later kills the student he used to stage the first crime, relying on diplomatic immunity to frustrate arrest. CIA operative Nelson Brenner’s cover as a speech-writing consultant begins to unravel after he kills a fellow agent, with the agency’s secrecy complicating Columbo’s pursuit.
Retired matador Luis Montoya kills his bookkeeper to hide the fear that would ruin his public reputation, and magician Santini murders the employer who threatens to expose his past as a Nazi prison guard. In the final case, Commodore Otis Swanson is found drowned and his son-in-law Charles Clay appears to be the killer; then Clay is murdered too. Columbo, Sergeant Kramer and novice Sergeant Mac Albinsky assemble the remaining suspects. Their reveal identifies Swanson’s nephew Swanny as the killer of both men, after he had planted evidence that led Clay to cover up the Commodore’s death. A typewriter ribbon preserves Santini’s blackmailer’s letter, exposing his motive. Salah confesses while the king listens from another room, then waives immunity to face prosecution in America rather than return home to the punishment he fears.