At 4am on April 21, 2016, Muktar Hussen woke up in the small flat he shared with his 31-year-old son, Mohamud Muketar, in Fitzroy.

The pair worked as taxi drivers and shared the same cab. Hussen drove the day shift and Muketar took over at night. Muketar usually arrived home late, leaving the car keys on the living room table for his father. But that morning, the keys weren’t there.

After searching the apartment, Hussen realised his son hadn’t returned home. His phone calls went unanswered. He was unperturbed – his son often went out with friends and sometimes did not return home until the early morning. Hussen took the spare keys.

On the street outside, police tape stopped him getting to his cab. He spoke to an officer, was referred to a senior detective. That’s when he found out. “He died.”

The police explained that Muketar had been stabbed to death the previous night, just metres from his home. Hussen’s next words were a question that is yet to be answered. “Who killed my son?”

This is the excruciating, all-encompassing unknown that has taken over the lives of Muketar’s family and friends, and one police are struggling to answer a year on from his death.

“The police said that it had happened and that they were trying to catch him, but I’m still waiting,” Hussen tells The Saturday Paper.

On that morning last April, Hussen went into shock. He had spoken to his son at 8 o’clock the night before, letting him know there was dinner waiting for him at home. Hours later, Muketar was murdered.

“He finished his job and he was killed on the street,” Hussen says.

This is what police know:

About 11.30pm on Wednesday, April 20, 2016, Muketar finished his shift and parked on Condell Street in Fitzroy, a short walk from his home.

He began walking home and turned south down Napier Street. Minutes later, a man crossed the road towards Muketar and stabbed him multiple times in the upper body with a knife, before leaving him on the side of the road.

Muketar’s money, phone and wallet were left behind by the killer.

A man and woman sitting in the nearby Condell Street Reserve are the sole witnesses to the crime. They saw the attacker run past and heard Muketar’s final cries for help.

They alerted police, but Muketar died on the street minutes later.

Police have described Muketar’s murder as brutal and savage. It was senseless, most likely random.

Muketar was a hard-working man. Most of the money he earned went to his mother and family in New Zealand. His family fled war in Somalia, spending time in a Kenyan refugee camp before settling in Wellington in 1994. Hussen has five other children, and moved to Australia for new opportunities.

“I’ve got a big family so I have to educate them, and Melbourne was an opportunity for money,” Hussen says.

From 2005, Muketar worked as a taxi driver in Brisbane and Melbourne, before settling in Fitzroy with his father five years ago. He thought of Melbourne as his home, loved the thriving neighbourhood and restaurants nearby, and closely followed soccer.

Hussen’s voice brightens when he talks about his son, slipping between the past and present tense.

“He was a very lovely boy, he was very good and respected, and all of his friends loved him,” he says. “Everyone in the community knew him, he didn’t have any enemies. He was so loving, he was a happy person.”

Muketar’s closest relationship was with his father. Their lives were closely intertwined.

“They were inseparable, sharing a house, a business and a friendship that was the envy of other friends,” says family friend Rhonda Garad.

“We lived together not like father and son, but like friends,” Hussen adds.

Muketar’s death shredded Hussen’s life, leaving him unable to work for four months. Garad led a crowd-funding campaign during this time to support him and cover funeral costs.

Hussen has since moved house and returned to work, restoring some degree of normality and routine to his life. But while his son’s murder remains unsolved, a single word rules his life: why?

“I told police that night, ‘My son has already died, but I don’t want this to happen to anybody else, so please, please try to catch that man,’ ” Hussen says through tears. “Why did they kill him? Who killed him? That’s the big question and we don’t have any answers.”

In the days following the crime, police canvassed CCTV footage in the area and appealed for witnesses. Just over a week later, they released CCTV footage of a cyclist they wished to speak to, and set up an information caravan on Napier Street. The police have now received 80 phone calls from the public about this case, but none have proved helpful.

“We’ve looked into his family history, his personal and social life, and there’s nothing that explains why he might have been targeted,” Detective Senior Sergeant Stephen McIntyre said at a recent press conference.

“We don’t know why the offender has crossed the road and approached him. It was a savage attack, it was a brutal attack and it was sustained for a period of time. Why that occurred, we don’t know – we don’t have the answers that we want to be able to give to the father.”

Detective Senior Constable Kane Taylor, who has been working on the case from the beginning, says the randomness of the crime has made it the most difficult type of case to solve.

“We have to cast the net so wide and can’t focus our resources on a specific person or a specific group of persons,” Taylor tells The Saturday Paper.

“It’s like a needle in the haystack. It’s not through a lack of trying, but it’s going to be a very tough investigation. It’s one we’re committed to solving and getting a result on.”

Despite interviewing a number of persons of interest – at one point it was incorrectly reported that charges would soon be laid – police have gained little ground. Last week, they called for public assistance with the case, releasing a composite image of the suspect and two new pieces of CCTV footage.

The first piece of footage is of the cyclist that police have been searching for since the night of the murder. Captured from Fitzroy Town Hall, the footage also shows a blurry, shadowy figure running up Napier Street and into the nearby reserve who police believe is the killer.

“It’s such a poor-quality image that unless you knew what you were looking for you may not have picked up what you were looking at,” McIntyre explains.

The cyclist then rides past seconds later, turning in the same direction the offender ran, before changing direction along Napier Street towards where Muketar was attacked seconds earlier.

“Whether they were aware what had actually taken place, whether they were aware that Mohamud was actually lying there on the side of the road, we don’t know, so we need to speak to that person,” McIntyre said.

Taylor says it is likely the cyclist saw or heard something on the night, and they are urged to contact police. “They were there, it was vocal, it was loud and other witnesses heard. The benefit to us could be phenomenal.”

The other piece of CCTV footage released shows a white Toyota Yaris “doing laps” of nearby backstreets just after the crime took place.

The car is seen entering a roundabout near Fitzroy Town Hall at least six times and leaving in different directions. The last time, the car drives right past a police officer setting up police tape near where Muketar was killed.

The car is then seen in different footage driving into a dead-end laneway behind the Napier Hotel twice, waiting for a few minutes, then leaving. “Whether they were looking to pick up the offender or whether it was totally coincidental, we don’t know,” McIntyre says. “But we need to find out.”

The car is the new focus of the investigation.

Taylor says rereleasing the footage and holding a public press conference is an effort to bring attention back to the case and try to bring witnesses forward. It’s a transparent approach from the police, and demonstrates just how difficult this case is.

“The main purpose was to bring it to everyone’s mind again and let them know where we’re at,” he says. “We want to put it at the forefront of people’s minds. There has to be someone that knows something.”

For Hussen, the unknowns surrounding his son’s death add another layer of grief and difficulty in his efforts to find meaning in the tragedy.

“The family and me, we are still not forgetting,” he says.

“Unless someone says, ‘This is the one who killed him’, until a judge says he’s guilty, you cannot forgive yourself. Every day in the morning I’m waiting for good news … every day. There’s no closure now. It’s open. Everyone is waiting, everyone in the community is asking what’s happening.”

Hussen is in regular contact with the police to receive updates on the investigation, with the ongoing search for justice consuming his life.

“Unless we finish this case, the problem will never finish and the question will always be there every day,” he says.

“The big question to me is why they killed him, and I still don’t have an answer.”