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.
Lt. Columbo is invited as guest speaker in a Criminology course and squares off against
two cunning students, who are confident they have duped the lieutenant with various leads, when their professor is found murdered.
Wade Anders, a former security expert, hosts the show Crime Alert. A rival host, news reader Bud, discovers Wade was in a porno movie and plans to tell the world then take over his show.
Lt. Columbo is pitted against an equally brilliant, nationally recognized criminal defence lawyer who murders his rock star girlfriend when he discovers she is seeing another man.
Nick Franco is a violent, two-timing gigolo and his current paramour, Laura Stanton, has had enough. With the help of a young woman named Lisa, she murders her lover and sets herself up with an airtight alibi. When Columbo starts sniffing on her trail, Laura quickly works to seduce the married detective, hoping that her sex appeal will throw the usually stubborn Lieutenant off the scent.
Ego-maniac Fielding Chase, is a radio talk show host who in order to prevent his daughter from moving to New York, murders a member of his staff.