The organisers of Britain's Parklife Weekender festival have offered up a $32,000 (£20,000) cash reward for information leading to the arrest of the person responsible for a fatal attack on a gig-goer. Robert Hart, 26, was at the Manchester event's main stage to watch rapper Snoop Dogg perform on 7 June (14) when he became embroiled in an altercation with another man after Hart's girlfriend was allegedly hit with an inflatable doll. Hart was reportedly punched to the ground and knocked unconscious. He died in hospital four days later (11Jun14). Greater Manchester Police (GMP) officials are currently on the hunt for a tall male with short, curly black hair, around the age of 25, who they believe is responsible for the fatal assault. Now Parklife bosses have appealed for help in tracking down the assailant. A statement posted on the festival's official Facebook.com page reads: "From the start we believed that, out of the 70,000 people at the festival, there must have been one person who knows who was responsible for this cowardly act. "After careful consultation with GMP, who have in turn been in extremely close communication with the (Hart) family, we are now able to offer £20,000 for information which leads the authorities to identifying the attacker and convicting him for the crime."