Related Clues:

• "Gosh darn it!"
• Users' nemeses
• Lab dwellers
• Divulges
• Sewer rodents
• Drug cops, for short
• Tattletales
• Charlie Brown's "Darn!"
• Unintentional poker table signals
• Candidates for witness protection programs
• Traitors
• Unwanted tenants
• Urban vermin
• Blows the whistle (on)
• Feds who make busts