Possible Clues:

• Hammett hero
• 1941 Bogart role
• Character described as looking 'rather pleasantly like a blond satan'
• 'When you're slapped, you'll take it and like it' speaker
• Private detective in Dashiell Hammett's novel 'The Maltese Falcon'
• 'The Maltese Falcon' detective
• Detective reportedly paid to follow mass movement
• Dashiell Hammett detective
• Hero who debuted in Black Mask magazine, 1929