Police have released a new appeal for information on the second anniversary of an attack which led to the death of Beyake Keita Ann.
It comes as Crimestoppers offer a reward of up to Â£10,000 for information they receive which leads to a successful conviction.
The 21-year-old was assaulted in Attock Park, Laisterdyke, on Tuesday, August 23, 2016.
He was playing football with friends in the park at around 8pm, when he was approached by a group of males who attacked him and one of his friends.
He suffered serious head injuries, from which he never recovered, and died in hospital on September 13, 2016.
A memorial is being held for him this afternoon in Attock Park from 3.30pm.
Following Beyake’s death police launched a murder investigation which led to the arrest of more than 20 males.
The inquiry is continuing and a number of suspects remain on bail in relation to it.
Detective Chief Inspector Ian Scott, who is leading the investigation, said: "We remain committed to getting justice for Beyake and his family, who are desperate to know why their son was attacked and who was responsible.
“We continue to believe the answers they are looking for will be found in the local community and we urge anyone with information to come forward and speak with our officers, or call the independent charity Crimestoppers, who guarantee 100 per cent anonymity to everyone who contacts them.
"We also ask for anyone who may have seen the incident or who may have information about those responsible to come forward and tell us what they know.
"There is also a possibility that circumstances may have changed in the last two years, and that those who felt they were not in a position to speak previously can do so now.
“If this applies to you then I please ask you to come forward and speak with my team. You may have that vital piece of information which will help us to solve this case and provide Beyake's family with some closure.
He urged people contact his team on 101, quoting crime reference 13160363829 and for those wanting to stay anonymous, contact Crimestoppers on 0800 555111 or useCrimestoppers-uk.org.
A new video featuring Det Chief Insp Scott will be shown at a community event for Eid in Attock Park today, held in memory of Beyake. The event will run between 3.30pm and 6pm.