The Maestro (The Spirit)
Murderous blackmailer who specializes in threatening swing bandleaders from the "Music Hath Charms" story of comic book The Spirit (1945).
He turns out to be the unnamed drummer from Lazo's band, and wanted to take over the band. The band's trumpeter, Ed, was also in on it.
Not to be confused with another swing music blackmailer from a different comic book with the exact same name, The Maestro.