(KTXL) — The San Joaquin County Sheriff’s Office is mourning one of its own after one of its police dogs, Duke, was killed in the line of duty while attempting to detain a suspect on Sunday morning.

Before becoming a police dog, Amie and Matthew Chapman were raising Duke to be a guide dog. 

However, they were not shocked when they found out Duke would be a police dog. 

The Chapmans said they followed Duke’s career from afar, with pride and relief that he had found his calling. However, it came with grief. 

On Sunday, the sheriff’s office said that they were called in for assistance by the Tracy Police Department regarding a burglary that occurred at a rail yard near Brichetto Road and South Banta Road.

According to the Tracy Police Department, two suspects were taking items from one of the train cars that belonged to Union Pacific Railroad. 

Police said when officers approached the suspects, one fled the scene, while the other, who was later identified as 30-year-old Rafael Montoya-Velazquez, hid inside an engine car. 

According to the sheriff’s office, after an officer from the Tracy Police Department saw the suspect enter an engine car officers surrounded the car and gave time for the suspect to surrender.

When the suspect did not surrender, Duke went in and searched for the subject. Duke engaged with the suspect and a fight ensued.

According to police, a stun gun was used to help detain Montoya-Velazquez. 

The sheriff’s office said during the fight the suspect stabbed Duke several times. 

Police continued to detain Montoya-Velazquez while deputies from the sheriff’s office took Duke to a nearby veterinarian. At the vet, Duke died due to his injuries. 

Police said Montoya-Velazquez had a “large folding knife that was used in the assault against Duke.” 

After the incident, Montoya-Velazquez was arrested and booked into custody, according to police. 

The Chapmans learned through social media that Duke had been stabbed and killed. 

“I always knew there was a chance that he could get harmed or get hurt, and I always knew he was so brave, be wouldn’t shy away from a challenge,” Matthew Chapman said. 

The Champans say Duke’s impact will be felt not just in his law enforcement community but also within guide dog communities around the world who continue to enjoy his training videos.