Caroline Elliott says it will be impossible to fill the hole left by Bruiser, who was shot dead in the driveway of her Willow Grove home in September.

But almost six months later, all she wants is an explanation.

Bruiser, seven, was killed instantly when he was shot by police on September 3, 2013, while police were at the Wendouree address as part of a separate investigation.

At the time police said the officers went through the front gate and were halfway up the driveway when the dog allegedly ran out the front door in a “threatening manner”.

The police member, who was fearful of being attacked, was forced to take protective action and fired one shot, police reported at the time.

But this is little consolation for Ms Elliott, whose beloved dog is buried in her backyard. 

She said a day never went by where she did not think of her former "best friend".

She has since bought two new puppies, a purebred and a crossbred staffordshire terrier, but they fail to fill the hole left by the dead bull mastiff.

"They won't fill the hole. Bruiser was everything to me," Ms Elliott said.

"You couldn't have got a better dog ... he was my companion, he was my lifesaver. It's just empty without Bruiser."

Ms Elliott said she had only heard from police once since the incident; two months after the shooting.

In the last four months she said she had not received any update.

"I still don't know why they shot him. I don't even know why they were here in the first place.

"I would have thought that, especially given the time of day (about 9am), they would be looking into it fairly closely."

Victoria Police says there has been no update in the investigation. Since the interview with Ms Elliott, The Courier has requested further comment