Related Clues:

• Turn state's evidence
• Long-tailed pest
• Burrowing rodent
• Gnawing problem?
• Despicable person
• Ship deserter
• Double-dealer
• Jailhouse singer?
• Field mouse
• "The Wind in the Willows" fellow
• Lab animal
• Meadow rodent
• Muskrat's kin
• Betrayer
• Blow the whistle (on)