SUNNYVALE (CBS SF) — A 25-year-old man fatally shot by a Sunnyvale public safety lieutenant after he allegedly stabbed his girlfriend on Tuesday afternoon has been identified by the department as Jesus Birelas-Contreras.

Officers had responded at about 1 p.m. Tuesday to a reported stabbing in the 500 block of East Weddell Avenue and arrived to find the 25-year-old victim.

READ MORE: UPDATE: Wind-Whipped Big Sur Wildfire Grows To 1,500 Acres, Blaze Erupts Near Geysers Peak In Sonoma

The victim had a stab wound to her abdomen and said Birelas-Contreras stabbed her during an argument, Sunnyvale Department of Public Safety officials said.

Birelas-Contreras was still inside the home, where the stabbing occurred, and did not cooperate with officers’ commands for him to come out.

Officers tried to negotiate with Birelas-Contreras and then tried to use a police K-9 to apprehend him, but he allegedly stabbed the dog with a knife.

The dog, named Jax, was taken to an emergency veterinary hospital but died there. Jax was a 4-year-old German shepherd who had been with the department for two years and helped in 26 arrests, according to public safety officials.

The dog’s handler, Stephen Eckford, was uninjured.

During continued negotiations with Birelas-Contreras, he allegedly threw a knife at officers, prompting a lieutenant to open fire and strike the suspect, public safety officials said.

READ MORE: Pipeline Of Illegal Weapons Shutdown; Four Arrested In San Mateo, Alameda County Raids

Birelas-Contreras was taken to a hospital, where he succumbed to his injuries.

“A loss of any life is tragic as it impacts everyone involved,” Public Safety Chief Phan Ngo said Wednesday afternoon. “For our department, losing Jax in the line of duty is heartbreaking. There’s a huge void in our hearts.”

Ngo said, “Our K-9s are not only our department members, but our family members. The tremendous support shown from the community and our law enforcement partners within the last couple of days have really helped us with the loss of Jax.”

Lt. Emmett Larkin, the lieutenant who shot the suspect, has more than 19 years of law enforcement service. He has been placed on routine administrative leave during the shooting investigation, public safety officials said.

Public safety officials said Birelas-Contreras was not known to the department prior to Tuesday.

The Department of Public Safety will investigate the case in coordination with the Santa Clara County District Attorney’s Office.

MORE NEWS: Facebook Faces Wrongful Death Suit From Family Of Slain Oakland Federal Guard David Underwood

TM and © Copyright 2017 CBS Radio Inc. and its relevant subsidiaries. CBS RADIO and EYE Logo TM and Copyright 2017 CBS Broadcasting Inc. Used under license. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. Bay City News Service contributed to this report.