DETECTIVES are renewing their appeal to catch Robert Hart's killer on the anniversary of his murder.

Investigating officers are set to return to Heaton Park — the scene of the 26-year-old's death — in a bid to jog the memory of revellers 12 months after the tragic event at last year's Parklife Weekender festival.

It is believed Robert, of Macclesfield, spoke to his attacker in defence of his girlfriend, Gemma Parry, as someone was hitting her over the head with an inflatable doll, but he was then violently attacked.

At the park's festival entrance, officers are set to station vehicles with electronic boards displaying appeal information about the case and contact details.

The boards and information points will remind revellers there is still a £23,000 reward for the person who provides key information leading to the conviction of Robert's killer.

Police have set up a dedicated appeal phone line — 0161 856 9283 — in the hope that someone who holds key details about Robert's death will get in touch.

They also want people to send pictures from last year's festival to helpbobby@gmp.police.uk A team of 30 detectives are working on the case and have travelled across the UK as part of their extensive inquiries.

They have interviewed more than 150 people and studied hours of video footage and hundreds of photographs.

Last year, two people were arrested in connection with Robert's death and were released without charge. Police have since stressed they are not Robert's killers.

Detective Superintendent Philip Reade, who is leading the case, said: "We are just that one phone call or that one photograph away from solving this case — it's as simple and straightforward as that.

"Robert's family are unable to move on.

"They are seeking answers as to why Robert was so brutally attacked.

"Solving this case will bring some closure to them even though the loss will leave a huge hole in their lives."

Anyone with information is asked to call police on 101 or Crimestoppers anonymously on 0800 555 111.