A Sheriff’s Department drug dog had to be euthanized after an off-duty accident Tuesday.

Kilo, a Belgian Malinois, was chasing a toy in the backyard of his handler, Deputy Gerald Ahern, when the dog suffered a paralyzing spinal cord injury, Deputy Jesus Bañuelos, spokesman for the Pima County Sheriff’s Department, said in a news release.

“He was diagnosed with trauma to his spinal cord from a broken piece of spinal disk,” Bañuelos said. “The veterinarians treated Kilo with every procedure available to them. Unfortunately, they were unable to restore any movement in Kilo’s rear legs” and the decision was made to euthanize the police dog.

Kilo was purchased by the Sheriff’s Department in November 2010 and was assigned to Ahern. After 12 weeks of basic training, Ahern and Kilo were certified by the National Police Canine Association in the specialties of narcotics detection and patrol.

The deputy and his dog were described by Bañuelos as “one of the most productive narcotics teams in the history of the Pima County Sheriff’s Department Canine Unit.”

Since February 2011, Ahern and Kilo conducted 263 narcotics searches. The combined total of Kilo’s seizures was 4,723 pounds of marijuana, 43 pounds of cocaine, 4 pounds of methamphetamine, a half-pound of heroin, and more than $1 million in U.S. currency.

One of Kilo’s most notable seizures was made Aug. 28. During the search of a commercial tractor-trailer rig, Kilo alerted to a wooden crate containing a large safe. As a result of this alert, the safe was opened and more than $300,000 in suspected drug-related currency was found.