J.G. Reeder is more like a very shy, retiring, British civil servant.
Columbo, of course, was invented by R. Austin Freeman
. Freeman invented the "inverted detective story", in which the reader knows all the details of the crime at the start of the story, and then watches the detective try to figure it out. Several of Freeman's "Dr. Thorndyke" books are inverted detective stories, just like Columbo.