BANGOR – An explosives-sniffing dog that came to symbolize increased cooperation between state and local agencies was euthanized this week after it was determined he had a debilitating disease that was getting worse.

BB, a 7-year-old German shepherd who has been with the Penobscot County Sheriff’s Office for more than two years, suffered from what his handler Deputy James Roy said Friday was arthritis that severely worsened in his spine. What began about a month ago as an apparent loss of interest in working and training as a bomb dog developed into seizures and convulsions, and the animal fell down and ran into things, Roy said.

“He couldn’t walk well and he was in a lot of pain,” Roy said.

The prognosis wasn’t good.

“He wasn’t going to work again due to the severity of the arthritis,” Roy said.

Roy had a tough choice to make for a dog with whom he had spent countless hours in training, searching for explosives and relaxing at home.

BB had proven effective at detecting explosives and potential danger. For two consecutive quarters, the dog was recognized by the U.S. Police Canine Association, the certification agency, for his outstanding performance. Last year, BB located grenades in Burlington and later, in October, a loaded handgun that a burglar had hidden in a home.

Acquiring BB was a joint effort between the sheriff’s department and the 101st Air Refueling Wing of the Maine Air National Guard, where Roy is a tech sergeant. Two years ago, the joint effort was described by an Air Guard official as something that they were hoping “will break the mold for not only the state but for the entire nation.”

BB’s condition worsened in recent weeks, and on Monday he spent the night at an emergency veterinarian clinic in Brewer. Roy made the decision Tuesday morning to put an end to BB’s pain.

“It was the best decision; it was the most humane decision for him,” Roy said.

A teletype went out that day to law enforcement agencies that BB had died.

Chief Deputy Troy Morton of the Penobscot County Sheriff’s Office credited BB and his handler with improving law enforcement efforts and relations in the region. He said that with so few bomb dogs in the state, the service that they provided is still needed. Morton said that the sheriff’s office doesn’t want the bomb-sniffing program to die with BB.

“We’re going to try to continue with the program, we don’t want that to stop,” Morton said.