Glaswegian Paul Walker, 52, was thought to be seeing in 2015 when he assaulted near his home in Blackpool, Lancs.
He was found unconscious on the ground and was rushed to Victoria Hospital but died shortly afterwards.
A post mortem examination showed the cause of death was head, face and neck injuries.
Officers believe film of the attack may have been was taken on a mobile device but it has since been deleted and detectives are attempting to retrieve it.
Today the boy, who cannot be named for legal reasons, admitted manslaughter.
He was initially charged with murder but in a brief hearing, prosecutors accepted his plea to the lesser charge and he will be sentenced on April 10.
Mr Walker who is believed to originate from the Pollok area of Glasgow, was a Celtic fan and had lived in Blackpool for at least 10 years.
Describing himself on Facebook as a ‘graduate from Glasgow Caledonian University’ he posted a series of photographs of himself in his Celtic shirt and images showing support for Celtic and previous manager Neil Lennon.
He also posted a series of photos of his young son.
His sister Harriet posted a photo online of the two of them together with the caption: “My lovely brother. Can’t take it in, we never see each other again.”
His nephew Luke said: “I’m in bits. We has such a good night as well. Then this happened.”
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