Columbo (season 9)

Temperamental artist Max Barsini (Patrick Bauchau) effectively lives with three women: his ex-wife, Louise (Fionnula Flanagan), his young live-in model Julie (Isabel García Lorca), and his current wife Vanessa (Shera Danese). Barsini takes delight in the way they fight for his attention. But when Louise begins seeing a therapist, Dr. Hammer (George Coe), who is also her new fiancé, Barsini fears she will reveal that he killed his first agent, who was robbing him. He kills Louise, then makes it look like she drowned at the beach while he was in his studio, painting. Columbo poses for Barsini while investigating him.

When Dian Hunter (Deidre Hall), the partner of men's magazine publisher Sean Brantley (Ian Buchanan), goes missing after expressing a desire to sell her 51% interest to a rival, suspicion falls on Brantley and his girlfriend Tina (Rebecca Staab). Columbo sets out to find the body, eventually digging up much of Brantley's estate. But once the event turns into a full-blown media event, Dian resurfaces, explaining she needed some time to herself. Sales and the magazine's value are increased by the controversy, but to Brantley's shock, she still intends to sell. He proceeds to then kill Hunter for real and hides the body, believing that Columbo won't fall for the same trick twice.

Oscar Finch (Patrick McGoohan) is a lawyer who uses underhanded methods to get his clients off, like coercing Paul Mackey (Denis Arndt), who worked for the D.A.'s office, into destroying evidence against racketeer Frank Staplin (Louis Zorich) in 1969. Twenty-one years later, Mackey is chosen by a presidential candidate, Governor Montgomery (Arthur Hill), to be his Vice Presidential running mate. Finch himself hopes that he might be appointed as the next Attorney General. Staplin, facing another indictment, threatens to expose the long-ago favor and ruin Finch's and Mackey's political futures if he doesn't arrange the destruction of another document. Finch decides to murder him. He scatters cigar ashes to make it seem he was in a late-night meeting with a contributor when the murder occurred. Finch walks to Staplin's house, shoots him and makes his death look like a suicide.

Final clue/twist: After Columbo learns, that Staplin hasn't eaten any of the cheese on the dish at the crime scene, but with a bitten off piece left behind, he assumes, that Finch must have taken a bite. CSI can fabricate a toothprint from the cheese and Columbo finds more than enough samples of Finch's toothprint on his disposed chewing gums - proving, that he was at the crime scene.

Vivian Dimitri (Helen Shaver) is a real-estate executive whose recently deceased husband had been sent to prison by Columbo. She seeks revenge by plotting to kill Columbo and his wife. But first she murders her boss, Charlie Chambers (Edward Winter), her husband's partner who avoided prison by informing on him. Vivian shoots Chambers in his office, using her affair with married Leland St. John (Ian McShane) to establish an alibi. Then she plants evidence to make it look like Chambers was killed by disgruntled residents of a new housing development. Her plan is then to kill the Columbos with a jar of poisoned marmalade. Roscoe Lee Browne plays her psychiatrist, Dr. Steadman.

Final clue/twist: Columbo fakes the death of his wife. After the "funeral", Columbo invites Vivian into his house. She makes him a sandwich with the (fake) poisoned marmalade. While Columbo acts like he's poisoned, Vivian confesses the murder.

Jess McCurdy (Brenda Vaccaro) fails to convince her sister, best-selling romance novelist Theresa Goren (Janet Margolin), to cancel her wedding to Wayne Jennings (Andrew Stevens), a playboy/tennis bum half her age and a golddigger. McCurdy impersonates her sister on the phone with Jennings and dumps him. Jennings reacts by killing Goren - twice. He arranges an alibi for the first murder, than shoots her again. The story is, that Goren was killed by a burglar and a furious Jennings shot at an already dead body (still a crime but not prosecuted as an actual murder).