They are wanted by South Yorkshire Police over the murder of 22-year-old Jordan Thomas, who was shot dead in a car at a set of traffic lights on Derek Dooley Way on December 21, 2014.
Jordan was blasted through the passenger side window of the Ford Mondeo he was travelling in when a gunman jumped out of a vehicle behind and fired three shots - hitting Jordan twice in his chest and the driver, who survived, once.
Drug dealer Jama Ahmed, 28, of Broomhall Place, Broomhall, was jailed for a minimum of 36 years for his role in the murder, which was described as a 'cold-blooded execution' by the judge who jailed him.
He was convicted on the basis that he was in the car from which the gunman jumped out and opened fire, and that he was part of the pre-planned assassination.
It could not be proved that he was the actual gunman who pulled the trigger and others involved in the attack were never tracked down.
Four men, now believed to be living in Somalia, are believed to hold vital information about the shooting.
Detectives released their names and photographs on the first anniversary of the murder, which was carried out by a gang in ‘revenge’ for the death of 23-year-old Mubarak Ali in 2011, for which Jordan's cousin, James Knowles, then 22, was jailed for 10 years after being convicted of manslaughter.
Gang member Mubarak, from Headford Grove, Broomhall, organised an ambush of Knowles in a barber's shop on Abbeydale Road, during which threats were made to kill and shoot him.
But Knowles, of Deer Park Road, Stannington, ended up stabbing Mubarek to death after they left the shop.
The men being sought by South Yorkshire Police over Jordan's murder, include two of Mubarak's brothers - Mohammed Ali, 31, and Jamal Ali, 28.
Detectives also want to trace Saeed Hussein, 28 and Ahmed Warsame, 29.
They are all believed to hold vital information about the shooting, which was said to have been the result of rival drug dealing gangs whose members used guns and knives against each other.
One gang was made up of men mainly from Broomhall and the other involved men largely from Pitsmoor and Burngreave.
A South Yorkshire Police spokeswoman said the investigation into the shooting is still underway.