Many criminals made a mistake by underestimating Lieutenant Columbo. Columbo is a homicide investigator, wearing a wrinkled windbreaker and driving a rundown car. He is undoubtedly an incompetent and clumsy person. But he was very polite to every suspect, and he talked too much about his wife (we have never seen her in any episode, but many people believe she later had her own show, starring Kate Mugrov and becoming famous for Star Trek: Voyager), to the extent that he even made even the shrewd murderer feel a false sense of security. Although the audience witnessed this murder case at the beginning of each episode, it is still surprising to see what mistakes the killer made in this seemingly perfect murder case.
