A man was killed at a Snoop Dogg concert after his girlfriend was hit in the head with a blow-up doll that was thrown in the crowd.
Robert Hart jumped to his girlfriend Gemma Parrys defence but died after a single punch was thrown during the headline act at Parklife Festival in Manchester in June 2014.
The then partner of Robert - who died in hospital five days after he was attacked - has now spoken out to make a fresh appeal for his killer to face justice 10 years on.
Ms Parry told how she and Robert - who was just 26 at the time - were inseparable and the trip to Heaton Park for Parklife was a surprise after they attended the festival the year before.
Roughly 70,000 people were at the festival that weekend, but to this day the man who punched Robert has escaped justice.
Robert Hart, left, was killed at a Snoop Dogg concert after his girlfriend Gemma Parry, right, was hit in the head with a blow-up doll that was thrown in the crowd
Ten years on, Ms Parry has made a fresh appeal for his killer to face justice. Pictured is an electronic image of the man police are looking for in connection with Roberts death
Detectives stressed the case remains unsolved but ongoing. A £50,000 reward also remains on offer for information leading to a conviction.
GMP investigators have trawled through thousands of photograph images and hours of mobile phone video footage, but say someone in the crowd may have unwittingly captured a still or film that could prove invaluable.
Robert was the youngest of four children. He grew up in Rainow, Macclesfield, and went to primary school in the village before attending Fallibroome Academy. He then went on to study art and design at Liverpool John Moores University.
Ms Parrys appeal comes as Roberts mother, Elaine Hart, told how the family prayed at his hospital bedside as he lay in an induced coma.
She described the attack as completely, completely unnecessary and told how Roberts future dreams had been taken away in an instant.
Ms Parry, speaking to the BBCs Crimewatch show this week, said: We were pretty much inseparable since the day we met. He was my best friend - he really was. And he never let me down.
Ms Parry said they had been to Parklife the year before and Robert got tickets again. The couple were with three friends.
It was raining, then the sun came out as soon as we got there really, she said. We danced, bought some drinks. We just sat there and spoke to people, just had a lovely time together.
Ms Parry said they went to watch the end of Rudimentals set and were waiting for Snoop Dog to come on.
There was an inflatable doll, she said. It got chucked over once then chucked back over. The second time, it hit me and covered me in mud.
And thats when Rob turned around. He actually said he didnt want any trouble. And thats when they have turned into a scuffle. I was trying to get Rob away and thats when I got knocked over. And then it was only within seconds that he came down next to me.
The 26-year-old jumped to his girlfriends defence but died after a single punch was thrown during the event at Parklife Festival in June 2014
Ms Parry told how she and Robert - who was just 26 at the time - were inseparable
Someone just said to me "we have got him back". The next thing I knew he was just apologising to me. He was dazed, you know. You think because people are telling you he is alright, he is alright. He was far from it really.
Manchester City fan Robert, who loved playing the guitar, was rushed to hospital but had suffered a catastrophic bleed on the brain. He died five days later.
Detective Sergeant Clare Smith, from GMP, told the BBC one punch can take lives.
She said: A punch was thrown and Robert was hit. He fell to the ground and lost consciousness. He was given CPR at the scene and he did come round and he was able to make his way to the medical tent. From there he got an ambulance to the hospital. Unfortunately, a few days later, he died.
One punch can take a life and it is a very tragic case. The person responsible may well not have been aware of the fatal impact that his actions had because he left the scene immediately afterwards.
The suspect is described as a mixed race man aged in his mid 20s and around 6ft 2in tall.
He had short dark hair shaven at the sides and was muscular. At some point during the festival, he was with a white woman aged in her mid 20s with shoulder length blonde hair, possibly wearing a pink T-shirt.
Detective Sergeant Smith said: We are hopeful that the passage of time may mean that those who didnt feel comfortable talking to us in 2014 may now feel brave enough to do so. If you witnessed the attack, or someone confided in you afterwards about what happened, we would like to hear from you.
If you were taking videos and photos at the festival, you may well have captured something that helps with the investigation. If you have something that you havent yet given to us, we would like to see it. Roberts family have had to live with this for 10 years now. We would really like to give his family some closure.
The forces dedicated email address is helpbobby@gmp.police.uk - or people can call Crimestoppers on 0800 555 111.