The incident began around 2 p.m. Thursday near the intersection of La Palma Avenue and West Street. Authorities say two Orange County probation officers conducting a house check were searching for a man on probation.
They encountered him on a street corner in the neighborhood with two other men, including 21-year-old Robert Moreno Jr. Moreno allegedly fired twice at officers and took off running, prompting the search.
"The Orange County probation officers showed up for somebody completely different, and he just happened to be with the individual they were supervising, so at this point it was an unprovoked attack," said Schmidt.
Anaheim police officers and "Bruno," a German shepherd police K9, responded to the scene and found Moreno hiding in a trash can. According to police, Moreno then opened fire, hitting Bruno. That's when officers fired back, killing Moreno.
Police say the original probationer was taken into custody. The third man escaped and remained at large Friday.
Police say Bruno risked his life to protect several officers during a standoff. On Thursday night, Bruno underwent emergency surgery to have the bullet that pierced his jaw, entered his chest, and punctured one of his lungs removed. Although Bruno survived the shooting, officials say he may not survive the surgery to restructure his jaw.
The Anaheim Police Department posted a photo of Bruno sitting up and looking better at about noon on Friday on its Facebook page. "Still has much healing to occur and still guarded prognosis but looking great!" the post reads.
"It's because of the trauma the dog received. It was a major surgery, and at this point, it did lose half its lung," said Anaheim Police Lt. Tim Schmidt. "We have to see what the next day is like for the dog."
Bruno was rushed to a local veterinary hospital where he underwent emergency surgery. Anaheim police say Bruno's actions spared human lives, and that they consider him a part of the family.
"He saved at least three police officers' lives last night and took the bullet for them," said Anaheim Police K9 Association President Cheryl Timmons.
Bruno is being called a hero for his police work, but more than that, he's the senior member of Anaheim's K9 Corps. He is Anaheim police Officer R.J. Young's partner, and a family pet.
"The connection between he and R.J., his handler, and R.J.'s wife and his 3-month-old baby is incredible," said Timmons.
Los Angeles Police Department Chief Charlie Beck, deputies from the Los Angeles County Sheriff's Department K9 unit, the Long Beach Fire Department and the Mountain View Police Department all sent their condolences.
"We've got tons of support from all the different agencies, but this is something that everyone rallies around," said Schmidt. "It's our dog, it's our K9 and we have tremendous love for dogs, but we are happy that everyone is safe and our dog is going to be able to survive this."
Bruno will remain in veterinary care for at least six weeks.
For more information on how you can donate to Bruno's current or future medical care costs, visit www.facebook.com/AnaheimK9friends.
The search continues for the outstanding suspect. Anaheim police have not released any other information.
City News Service contributed to this report.