Police investigating the attack on Robert Hart at Parklife Weekender Festival in Manchester have released new information in the bid to identify his killer.
Robert, 26, was assaulted near the festival's main stage at around 9.15pm on Saturday 7 June 2014 and tragically died several days later as a result of his injuries.
Police have now issued a photograph of the area where the assault took place and are urging people who believe they were in that area at the time of the attack to send any pictures and video footage they may have taken.
Witnesses at the festival have suggested the offender was not alone at the festival, and that he was shepherded away from the area by friends following the attack.
In particular, a woman who dragged the attacker away from the area in the immediate aftermath is described as white with blonde, shoulder-length hair, standing around 5ft 7in tall and approximately 20-23 years old.
She was wearing a pink top with a dark jacket over the top.
They were also in the company of a white man standing at around 6ft1in tall and wearing a dark jacket.
Robert's attacker is still being described as a mixed race male, aged in his late 20's and around 6ft 1 tall. He has a muscular build and short, dark hair which was shaved at the sides.
Detective Inspector Richard Eales said: "Several witnesses have pointed towards the fact that this man was at the festival with other people, notably the girl we have described today.
"We want people who were in the area at around the same time of the attack to send in your photographs and video footage.
"There is a strong chance that the person we are looking for, or the people he was with, could be in the background of those pictures or footage and that may prove invaluable to our investigation.
"I am now appealing directly to the man responsible, the girl who was with him and any other friends that might have travelled to the festival with them: come forward.
"We are currently looking through thousands of pictures, hundreds of hours of CCTV and mobile phone footage and more are being sent to us all the time.
"There remains a £20,000 reward in place for information leading to the arrest and conviction of the man responsible."