MINOR SUPER-VILLAIN 816: THE MASTERMIND

(The Spirit, "the Mastermind Strikes", 6 October, 1940)

The Mastermind is really Joel Kenner, a mayoral candidate who tries to get his Tough on Crime campaign a boost by murdering both of his campaign managers and blaming the deaths on the Spirit. This ends poorly for Kenner, who ends up stabbing himself with his own knife like a complete dolt.

MINOR SUPER-VILLAIN 757: THE MASTERMIND

(Smash Comics 017, 1940) 

The Mastermind, mysterious head of a jewel theft and smuggling ring, is actually Jason White, prominent jeweller, but he is also Rufus Kane, pawnbroker and fence. White established Kane as a patsy identity to absorb all of the suspicion of being the Mastermind until things get a little too hot, at which point Kane and the Mastermind disappear and Jason White is free and clear to enjoy his ill-gotten gains.

And it works! Rufus Kane manages to escape from the Invisible Hood and the police! It's not quite the perfect crime - I'm sure that a little forensic accounting would turn up some irregularities in White's finances, for instance - but it's close enough. Unfortunately for him, the Invisible Hood is on the case, though for once invisibility is not the key to the situation. Instead, White is caught when the Hood, as Kent Thurston, gets his buddy Police Inspector Battle to tell him that Kane is no longer a suspect and he proceeds to sashay past the two of them in his Suspicious Criminal cosplay. An ignominious defeat to be sure!

MINOR SUPER-VILLAIN 057: THE MASTERMIND

(More Fun Comics 049-050, 1939)

Masked spy chief. After his first appearance is foiled by adventurer Biff Bronson he pulls one of the more major pivots in supercrime by opening one of those wax museums that doubles as a murder palace, where he himself is killed in a second encounter with Biff.