The case has also baffled police, who are trying to piece together the circumstances leading up to the murder.

Antonio 'Tony' Salaris was attacked near his home on Browning Street at Kilsyth about 9am on Wednesday by an unknown man.

The 73-year-old's body was found by neighbours, who only caught a glimpse of the killer before he ran off. He remains on the run.

"We don't know how the altercation occurred, why it occurred, how Tony came to leave the house and end up out on the street," Homicide Detective Inspector Tim Day told reporters on Thursday.

"The only thing we do know is shortly before 9am we know that it's a male that's attacked Tony, we know that Tony's been stabbed."

Det Insp Day said the only description police had of the killer was that he was a male. Investigators are even unsure of the direction he fled and have no murder weapon.

Mr Salaris' wife of 49 years Helen said she last saw her husband when she left home about 6:30am. He had planned to spend the morning practising the guitar.

She said he was a dedicated father and grandfather who loved spending time in the garden, planting fruit and vegetables for his seven grandchildren to eat.

"We want to know why, when there's really no reason for it at all," she said.

Daughter Amy said she continues to replay her father's last moments in her head.

"If they wanted money out of him he would have said here's my wallet take it," she said.

"It's important to all of us, his kids, his grandkids, to know why this happened," daughter Stephanie said.

"It's absolutely cruel to do that to us, to do that to him, to take his life for no reason."

Australian Associated Press