In this Tuesday, May 30, 2017, photo Massachusetts State Police K-9, Maximus, searches a car for drugs with Trooper Brian Bonia, left, during a training session in Revere, Mass. During drug raids, police dogs literally follow their noses to sniff out narcotics, but now the powerful synthetic opioid fentanyl could be deadly to the K-9s. Police have a new strategy for protecting their four-legged partners, by carrying Naloxone for their dog, the same drug to reverse heroin overdoses in humans. At right is Mass. State Trooper Brian Cooper. (AP Photo/Charles Krupa)