Related Clues:

• This line or the next, e.g.
• Padlock partner
• Game with Miss Scarlet and Professor Plum
• Bit of help
• It'll get you in
• Fingerprints, e.g.
• Shift, for one
• Lock partner
• ''The Defense of Fort McHenry'' author
• Musical signature
• Holmes quest
• Criminal game?
• Sleuth's aid
• Sleuthing aid
• Vitally important