*** Deadline, John Dunning, 1981
The introduction indicates that Dunning wrote this in six weeks and, unlike his other books, sold it immediately without a single rejection. It's not hard to see why. It's a page turner, from start to finish, all 253 pages. Dunning mentions the coincidence of the similarity to the movie Witness, which came out four years later, but it is evidently just that, a coincidence.
Recommended for whodunit fans.