The dog believed to have killed a woman in her 50s at a licensed kennel facility in the Perth suburb of Southern River will be euthanised.
The City of Gosnells issued a statement late on Wednesday afternoon which said police believe the Bull Mastiff, currently being held by the City, caused the death of Sue Lopicich.
A second dog, a Staffordshire Bull Terrier, was not involved in the incident.
"The Bull Mastiff has been surrendered and will be humanely euthanised by a vet," the statement said.
"The police advised the Staffordshire Bull Terrier was not involved and he will be returned to the family.
"The City extends its sincerest sympathies to Mrs Lopicich's family and friends."
Lee, a family friend, told Radio 6PR's Oliver Peterson that the dog was "well known for being aggressive," but that she loved it anyway.
"Being a rescue dog, it doesn't matter what the breed is, any dog can be aggressive if it's abused as a young dog and any dog can be a dear, loving dog regardless of its breed. And this one was unfortunately abused when it was young and she rescued it.
"And anyone knows who's been around abused dogs that they snap, just over nothing, over the smallest things, and unfortunately she was in the wrong place at the wrong time."
"The best way I can put it is that she thinks every dog deserves a second chance and she just loved every dog that came through there. She was a very caring woman."
The incident occurred on Tuesday afternoon at Barko's Boarding Kennels and police were called to the facility at around 1.30pm.
Mrs Lopicich, who owns the facility on Terrier Place, received life threatening injuries from the dog and she was declared dead by St John Ambulance officers.
Her death is not being treated as suspicious and a report will be prepared for the coroner.
The City of Gosnells said earlier how its rangers received a request from the police to attend the property to collect a dog, which was preventing officers from accessing her body.
"As a result, the City is currently holding two dogs that were taken from the property," the council said in an earlier statement.
"The adult, male dogs, one a bull mastiff and the other a Staffordshire bull terrier, are being held at the request of police.
"An investigation is being conducted by the police and the City is waiting to hear further from them.
"The dogs are microchipped and registered to the owner of the property.
"No previous complaints have been made to the City about these dogs."