Related Clues:

• Defendant's testimony, maybe
• "I was walking the dog at the time," e.g.
• ''Airtight'' story
• Accusation beater
• Perp-to-cop story
• It could clear you
• "Perfect murder" component
• What an accused perpetrator needs
• Cover, so to speak
• Perp's story
• It may help one get away with murder
• Suspect's trump card
• Grafton's "A"
• Out for a trial
• Whodunit staple