Officer 666 is a comic mystery novel by Barton Wood Currie that was adapted into a successful Broadway play in 1912. The story involves art theft, mistaken identity, and a hapless young man forced to impersonate a police officer — providing the kind of farcical complications that made the piece a hit with Edwardian-era theater audiences and novel readers alike.
A fun example of early American comic crime fiction, Officer 666 is freely available as a public-domain EPUB at Better Gutenberg.