Many criminals made the mistake of underestimating Lieutenant Columbo, a homicide investigator with a crumpled trench-coat and a beat-up car, who certainly acted as an incompetent bumbler.
But he was so polite to every suspect, and he talked so much about his wife (who we never got to see on any episode, but who many believe later had her own show, starring Kate Mulgrew, later of Star Trek: Voyager fame) that he lulled even the shrewdest murderer into a false sense of security.
And although the audience had witnessed the murder in the beginning of each episode, it was still a surprise to see what mistakes the killers had made during the seemingly perfect murder.
Ward Fowler, who plays debonair television detective Lieutenant Lucerne, has a reputation for being a difficult actor. His series is a hit, however, so the network and studio executives again and again capitulate to his demands. Although separated, husband and wife team Sid and Claire Daley continue to produce the Inspector Lucerne program. Claire continually advises everyone else to go along with their stars demands. Not even Sid knows that Claire is blackmailing Ward. Claire discovers Ward in Canada. She knows he deserted from the United States Army during the Korean War. If that information got out ,it would ruin Ward's career. When Claire takes a phone call in Ward's trailer, the actor overhears her saying she’ll be getting a sandwich at Tony’s Deli. Ward gets to Tony’s Deli just after Claire disguising himself with a ski mask and bulky parka he pretends to be a hold up man.
The female head of a museum hires one of the guards to rob the museum to collect the insurance money. But during the robbery she kills him and her own brother, and makes it look like they killed each other. The guard/robber's brother reports a strange message on his answering machine, that makes it seem that he has been killed. And Columbo gets the case. When Columbo first comes to the crime scene, he notices that the lights are off, a gold medallion in the robber's pants, and signs that pointed to the fact that he was going abroad after the heist. And he concluded that these clues mean that someone else was involved.
Two former college friends, now partners in an accounting firm, become enemies when one realizes the other has embezzled funds. The reason for his embezzling ways is his wife, she demands nothing but the best.