Columbo (season 3)

Cosmetics queen Viveca Scott (Vera Miles) has developed a seemingly magic wrinkle remover, but her former lover, Karl Lessing (Martin Sheen), a chemist for her company, intends to sell the formula to Scott's ruthless rival, David Lang (Vincent Price). Lessing refuses to sell it back to her at any price. Taunted by Lessing, Scott bludgeons him in a fit of rage and covers up her tracks as best she can, inadequately, as it turns out. Lang's secretary, Shirley Blaine (Sian Barbara Allen), who has been giving info to Scott about Lang's operation, has an unhealthy attraction to Scott and becomes a potential blackmailer. Scott manages to kill Blaine rather ingeniously.

Final clue/twist: After a relentless and grueling pursuit by Columbo, Scott, the cosmetics queen, is done in, by of all things, poison ivy. Columbo, noticing Viveca itching and suffering the same, realizes that they must both have had contact with the poison ivy from the same source. He claims his brother-in-law is a dermatologist and has diagnosed poison ivy. However, poison ivy does not grow in the Los Angeles area due to its desert dryness. Scott suspects the wrinkle remover, which she gets rid of by throwing it out of the window into the ocean, is responsible for her itching. However, Columbo explains that the poison ivy was actually on the lens of Lessing's microscope, shards of which they both touched.

Wine connoisseur Adrian Carsini (Donald Pleasence) runs a small winery specializing in unprofitable but prized wines. He is so highly regarded that he is about to be named the industry's Man-of-the-Year. His half-brother, Rick (Gary Conway), only wants to spend money on various hobbies and interests like sports and fast cars and has also been married several times. When Rick gets tired of Adrian's indulgences, he announces his decision to sell the land to mass producers of cheap, profitable wines. Adrian knocks him out and leaves him to die in an airtight wine cellar. He travels to New York to accept an award and attend wine auctions, establishing his alibi. Upon his return, he concocts a scuba diving accident to cover the crime. Columbo appears to befriend Carsini while slyly searching for clues to link him to the murder. Julie Harris plays Adrian's formidable secretary, who early on realizes that Columbo suspects Carsini of killing his brother. She has plans of her own, nonetheless.

Harry Stone (Ken Swofford), a campaign manager for Nelson Hayward, is coercing the womanizing senatorial candidate (Jackie Cooper) to end his affair with a personal secretary (Tisha Sterling), which Stone regards as too risky during a campaign. Stone, however, does approve of a publicity stunt Hayward plans to pull, which involves fabricating death threats against himself, to promote his tough stance against crime. Hayward then uses this to his advantage: he lures Stone to Hayward's beach house (while driving Hayward's car and wearing Hayward's coat), where the candidate shoots and kills Stone, making it look like a case of mistaken identity as a result of the imaginary assassins.

Final clue/twist: When he realizes that Columbo is coming closer and closer to a solving the murder, Hayward stages an assassination attempt by shooting (with a silencer) through a balcony window into his hotel room and later gets rid of the gun. Hours later (after he returns into the room and ignites a firecracker to mimic a gunshot) he claims that someone just shot at him from the outside and he demands that the bullet in the wall be analyzed. A very calm Columbo reveals that the ballistics of the bullet are already in and that it indeed was fired from the murder weapon. Before Hayward had returned, Columbo searched the room and found the holes in the window and in the wall along with the bullet -– hours before Hayward claimed someone had just shot at him.

Dr. Bart Keppel (Robert Culp) is a "motivation research specialist" who has made a name for himself on the subject of subliminal advertising (which involves inserting frames of an advertised product into the reels of a film, so subconsciously a viewer's mind will crave what is pictured). Keppel's more lucrative sideline is blackmail: he takes pictures of married clients with a girl hired to tempt them. When his latest victim, Vic Norris, refuses to be blackmailed and threatens to expose him, Keppel plots to kill him. First Keppel plants a dish of salty caviar at a reception he is hosting for his clients. A subliminal cut of a refreshing drink is used to lure Norris out of a screening room where he is watching a promotional film Keppel is supposedly narrating (in fact they are listening to a prerecorded narration). Keppel sneaks out and shoots Norris in the building lobby, then arranges things to appear the crime was committed by Norris's wife. When Keppel's projectionist Roger White (Chuck McCann) discovers the cuts and pieces together the plot and tries to blackmail him, Keppel shoots him as well.

Final clue/twist: Columbo incriminates Keppel using his own science by showing him a film laced with subliminal frames of images taken of where the murder weapon was supposedly hidden, leading to the discovery of the weapon, the only piece of evidence Columbo still needed.

Publisher Riley Greenleaf (Jack Cassidy) decides to kill his prolific author Alan Mallory (Mickey Spillane) to keep him from defecting to another publisher. He hires ex-con and avid homemade bomb enthusiast Eddie Kane (John Chandler) to do the job. While Greenleaf is getting drunk at a nearby bar, Kane walks into Mallory's office and shoots him. To cover his tracks, Greenleaf then kills Kane with one of his own bombs, making it look like an accident. Columbo must discover the link between the two crimes.

Final clue/twist: Greenleaf hands over an old synopsis (saying it was Kane's) to Columbo, allegedly proving that Kane had the idea for Mallory's newest book and murdered him out of revenge. Columbo finds out, though, that the ending of the book was actually developed shortly before the murder by Mallory and his new publisher's assistant (played by Mariette Hartley), to make sure the book was more attractive for Hollywood. Kane could not have known that, so the synopsis must have been fabricated by Greenleaf.

When Dr. Howard Nicholson (Lew Ayres) threatens to expose Neil Cahill (Robert Walker Jr.) for plagiarizing a paper from a recently deceased scientist, Neil's father, Dr. Marshall Cahill (José Ferrer), director of a high-tech Pentagon think tank, kills Nicholson to protect his son. He installs a cybernetic robot codenamed MM-7 (Robby the Robot) to take his place overseeing a war exercise. The elder Cahill steals a car from the motor pool and drives to Nicholson's house. In the driveway, Cahill runs over Nicholson, then carries his body into the house, ransacking it to make it look like a burglary gone wrong. To cover up damage the car received from the impact, Cahill backs his own car into the death car. Jessica Walter plays Nicholson's wife, who just happens to be Neil's psychotherapist.

Gospel-singing superstar Tommy Brown (Johnny Cash) is hugely successful. But he's unable to enjoy the usual benefits of his fame and wealth. His zealous wife Edna (Ida Lupino) can prove he had committed statutory rape with one of his backup singers, Maryann, when she was underage. With this proof, she blackmails him into abstaining from enjoying the company of other women and even from spending the proceeds from his own concerts. She wants every penny to go towards building a tabernacle for the Lord.

One day, Tommy decides he's had enough and decides to kill Edna and Maryann. He drugs both women to sleep on their small, private plane flight to Los Angeles, and then parachutes from the plane before it crashes into desert mountains. Brown lands in the desert but hurts his leg. He hides the parachute and lies down near the burning plane wreckage, making it seem like he was thrown clear in a tragic crash caused by flying through bad weather. Edna's brother Luke (Bill McKinney) insists the police handle the case as a homicide, while the FAA is ready to write it off to an accident.

When Hugh Caldwell (Michael McGuire) accidentally kills his wife in the heat of a fight, he doesn't call 911 but rather his friend and neighbor, LAPD Deputy Commissioner Mark Halperin (Richard Kiley). Halperin helps Caldwell cover up the crime and forces him to assist the following night in the murder of Halperin's own wife (Rosemary Murphy), a wealthy heiress whose money Halperin, a gambler, covets, Halperin arranges it so it seems that a cat burglar (Val Avery), who has recently been active in their neighborhood, is seen as the culprit in both killings.

Final clue/twist: When Columbo realizes what happened, he enlists the burglar's help in catching the true murderer (Halperin, who will inevitably give Caldwell up). Columbo creates fake files for the "burglary investigation" on which Halperin had ordered him to concentrate. While perusing the file, ostensibly to help Columbo, Halperin takes a glance at the address in the "police report", and he later hides jewelry taken from one of the murder sites at that location. Later, when Halperin calls for and leads a search of the "burglar's apartment", Columbo reveals that he himself is renting the rather seedy and threadbare apartment. Since only Columbo and Halperin knew this address, it is clear that Halperin had planted the evidence there, and was involved in the double murder.