What Was Unusual About "Columbo"?

The most unusual thing about this 1970s detective series starring Peter Falk was that, for the audience, there was no "whodunit" element. Instead, the viewer is taken with the murderer to see the killing at the start of every feature-length episode. The interest of the programme is in seeing the unorthodox methods of Lieutenant Columbo, the efforts of the villain to evade justice and, above all, the performance of Peter Falk as the detctive. His Columbo is said to be based on Petrovitch in Dosteovskey's "Crime and Punishment," and the character certainly makes a special impact. He is shambolic, unkempt, permanently clad in a dubious raincoat, and disarms suspects by appearing half-witted. He is usually seen squinting (Falk has a glass eye) through a haze of cigar smoke, rambling vaguely about the never-seen (except in a later spin-off)"Mrs Columbo" and then suddenly asking a pertinent question.
A new series of Columbo was made in the 1990s with Falk still in the title role.

Well answered, wordy! Also, Columbo used to do a long ramble at the suspect, giving every sign of having only half a brain, then he would start to leave the suspects home or office or wherever, and turn back with a 'oh, by the way...' question. The suspect was always so convinced by then that Columbo was a complete idiot, that they would accidentally let some vital clue slip whilst answering this apparent after-thought question. It was a very good series to watch on Sunday afternoons, vegging out on the sofa...