The devastated family of a man found stabbed to death on a Melbourne footpath have no idea who would want to kill the beloved grandfather of seven.
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.
"We're asking any neighbours, residents in the area that may find a knife or an edged weapon in their gardens, their front yards, in any parkland, in any gutters to contact police immediately," he said.
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."
She said her father, who had suffered a stroke five weeks ago, also had another grandchild on the way.
Det Insp Day appealed for residents with CCTV or dashcam footage from the area at the time to come forward, as well as anyone who may have seen someone unfamiliar in the area.