The 17-year-old West Highland Terrier, named Scruffy, was found dead with a towel from the family's clothesline tied around his neck at Northam Avenue, Bardon.
The towel was then tied to a plant.
Liam and Cath Proberts were in Sydney at a wedding when their son made the awful discovery on Friday.
A stringy old towel taken off the clothesline had been used to tie up the West Highland terrier, who had been in the family since the inner-west Brisbane couple's eldest daughter's sixth birthday.
"We were all, our initial reaction was just disbelief and then anger, really angry, like how the hell, it's unfathomable," Mr Proberts said.
"How could and who could do this?"
The pet appeared to have been killed near the clothesline before being taken from the side of the house into the backyard and "displayed" in full view of the main lounge room.
Police described the killing as a "sickening attack", saying there was blood found at the scene.
Detectives announced an animal cruelty investigation on Monday, calling for public assistance from anyone who may have seen what happened in the luxurious Bardon home's backyard between 10.30am and 3pm on Friday but no one was home.
An easement runs past the back of the home but Mrs Proberts said Scruffy had been quiet in his old age and would have been difficult to see from the tree-filled park.
The Proberts family was hoping some of that blood could have been the attacker, giving police a chance to match the DNA.
"I actually would really like to catch whoever did it," Mrs Proberts said.
Mrs Proberts said Scruffy hadn't barked for the last year because he was so old.
"Our neighbours said they didn't even know we had a dog," she said.
The family can’t imagine who would do such a thing to their “defenceless” pet who could barely walk up the stairs.
It's believed Scruffy was attacked sometime between 10.30am and 3pm on Friday, police said in a statement on Sunday night.
Anyone with information is urged to contact Crime Stoppers 1800 333 000.
(AU News Yahoo - April 24, 2017)