A Perth family have described the traumatic moment their dog turned on them in a frenzied attack that ended with the animal being shot dead by a police officer.
Michelle and Stephen Quayle were at their Vernon Gough Drive home in Baldivis in the city's southern suburbs with their dog Ace, a three-year-old blue heeler they adopted a month ago, when the attack happened.
The Quayles were told when they adopted Ace that he had a traumatic background.
Mr Quayle said he was sitting on the floor of his office about 6:30pm when his wife walked in, with Ace following her.
Ms Quayle rushed to help her husband.
"[Stephen] tried to push him off. I tried to grab him, but he was so strong. I tried to pull him off, it took all my might. Then I got him out the office and slammed the door shut," she said.
The dog then turned on the couple's daughter, biting her arm.
She barricaded herself in her bedroom and the family called the police.
'Three shots' needed to kill dog
Michelle Quayle said before the police got there, Ace was throwing himself at the doors trying to get in.
"When the police came to the door, I had to come out to let him in and he [Ace] just attacked me. He lunged onto my leg," she said.
Mr Quayle then had to wrest the dog off his wife.
"I threw him at the police officer and I said "Shoot him! Shoot him!" and he did. It took three shots. It took three shots to kill him."
Mr and Mrs Quayle said the were in shock over the attack and also the loss of Ace, who they thought would be their forever dog.
Both believed Mr Quayle could have died if not for a post-surgery plastic collar the dog was wearing after surgery.
Police close at hand
WA Police Senior Sergeant Ian Francis said an officer was only 500 metres away from the house when they got the call.
"The officer's gone inside the home, he's made contact with the other family members, and it was at that point the family dog had come back into that area where the family members were and attacked the wife in front of the police officer," he said.
Sergeant Francis said the dog had latched onto the woman's leg before the officer shot it twice.
Seeing it was critically injured, he shot it a third time to euthanise the animal.
"We don't like harming animals but given the circumstances, that level of force was required to reduce the threat to the family and to the officer himself," he said.
Sergeant Francis agreed the plastic collar prevented further injury to Mr Quayle.
Police will undertake an internal "use-of-force" review, a standard protocol when an officer fires their weapon.
All three family members required medical treatment for their injuries.
Attack highly unusual: RSPCA
The RSPCA's Hannah Dreaver said seeing dogs act so violently and out of character was unusual.
"But we never know the impact that stress can have on a dog or exactly what may have triggered this behaviour," she said.
"I wouldn't say it's a common behaviour. It's not something we see often.
She said in her eight-and-a-half years at the RSPCA, she had never heard of an adopted dog lashing out so violently before.
"Across the community in Perth, thousand of dogs are adopted into homes every year from lots of different rescues, and adopted dogs can make the most wonderful pets," she said.
"Just because you buy a purebred dog, doesn't guarantee that something like this would never happen."
