Related Clues:

• Insider informant
• Most valuable edges of plant
• Lawn disruption
• Term popularized by le Carré
• Jetty; animal
• Burrowing pest
• CIA turncoat
• Saboteur, e.g
• Burrowing spy?
• Penetration agent
• Shrew cousin
• Hedgehog's cousin
• Tunneling critter
• Spy also called a "sleeper agent"
• Spot troublesome animal in garden?