Police investigating the attack on Robert Hart still want to talk to two witnesses.
Twenty-six year old Robert, from Macclesfield, was viciously attacked after stepping in as his girlfriend, Gemma Parry, was repeatedly hit with an inflatable toy at the Parklife Festival in Manchester.
Police released images of festival-goers they believe could hold the key to catching Robert Hart’s killer.
Three of the people pictured came forward and this week a fourth potential witness has been identified.
But officers are still hoping to identify two witnesses who they believe were nearby when Robert was punched to the ground at the Heaton Park event at around 9.15pm on June 7.
Robert’s mum Elaine Hart, who lives in Bollington, urged anyone with information to come forward. She said: “We need them to come forward and identify themselves.
“If anyone knows anything at all, please come forward.”
Robert was a former pupil at Fallibroome Academy, which is planning a lasting tribute to the former student.
He died in Salford Hospital five days after the attack in which he suffered a bleed to the brain.
DCI Phil Reade said: “One of these people could hold the key to unlocking this investigation without even knowing it.
“Obtaining evidence such as that would represent a big step forward in this investigation.”
Anyone with information should call police on 0161 8569283 or email mit.syndicate8@gmp.police.co.uk.
