Melb cabbie's murder remains a mystery

When Melbourne cabbie Muktar Hussan went to pick up the taxi he shared with his son he made a grim discovery.

Mohamud Muketar, 31, was dead. He was murdered in a savage and prolonged stabbing attack while walking home in Fitzroy about 11.30pm on April 20, 2016.

A composite image of his suspected killer and CCTV of a white Toyota Yaris driving in the area at the time were released by Victoria Police on Friday.

Mr Hussan said his son was a good man, trying to lead a normal life and didn't have a problem with anyone.

"Why him? That's the question," Mr Hussan told reporters.

The father and son refugees from Somali came to Australia to "change our life" and earn money to support their large family.

"(Now) one of them is lost," Mr Hussan said.

Almost a year on from the murder, homicide detectives still aren't sure about the motive for the attack.

The killer deliberately crossed the road to get to Mr Muketar but a small amount of cash carried by the driver wasn't taken.

"He was savagely attacked, it was a brutal attack and it was sustained for a period of time," Homicide Squad Detective Senior Sergeant Stephen McIntyre said.

Police are hunting for a man of Caucasian appearance, aged 20 to 40, about 183cm tall with a lanky build and shoulder-length sandy blond hair that recedes at the top.

At the time he was wearing a dark top and dark pants, which may be jeans.

The late-model Yaris was seen driving in the area about 10 minutes after Mr Muketar was killed and did laps of Moor and George streets in Fitzroy,

It was also parked in a nearby alleyway for up to three minutes a number of times.

Police are also appealing a cyclist caught in CCTV footage, that also briefly depicts the killer, to come forward.