A top detective has condemned a wall of silence around the murder of Bradford student Anowar Tagabo.
The 25-year-old peace studies student at the University of Bradford died more than a week after suffering a head injury in a street attack in Sheffield.
Mr Tagabo, who was living in Bradford and had completed the first year of his course, had travelled to Sheffield for a wedding and was out celebrating in the city centre when he was attacked.
The assault happened in Carver Street at about 4.20am on Sunday, May 25, and Mr Tagabo, who was originally from Sudan, died in hospital on Tuesday, June 3.
South Yorkshire Police said the victim had become separated from a friend and was jogging in Carver Street with an unknown companion when they came across a group of men and the attack took place. Mr Tagabo's companion was chased from the area and has not been traced.
The detective leading the hunt for Mr Tagabo's killer today criticised the lack of courage of people who could help the police inquiry.
Detective Chief Inspector Natalie Shaw believes that at least half a dozen people saw the student being attacked.
She said: “I can’t believe that no-one has yet had the courage to come forward and tell the police what they saw.
“From CCTV we can see that at least half a dozen people directly witnessed what happened. That includes the unknown male who was with Anowar at the time and who was chased from the scene by a group after the attack.
“If they are fearful in whatever way, I want to reassure them that they can contact police in confidence, or ring Crimestoppers anonymously. Either way, we need to speak to that person and I would urge them to come forward.”
The area was busy at the time of the assault. A forensic post-mortem examination concluded that Mr Tagabo had died from a head injury. There is no known motive for the killing.
The victim had homes in Bradford and Leeds, and a cousin living in West Yorkshire.
The University of Bradford is assisting police with their inquiries.
Anyone with information should call South Yorkshire Police on 101, quoting incident number 281 of 25 May, 2014, or Crimestoppers, anonymously, on 0800 555 111.