Related Clues:

• Turn state's evidence
• Long-tailed pest
• Garfield, for one
• Gnawing problem?
• Despicable person
• Ship deserter
• Double-dealer
• Jailhouse singer?
• "The Wind in the Willows" fellow
• Lab animal
• Betrayer
• Blow the whistle (on)
• Ben, in a film
• Name names
• Lab critter