FOR almost 30 years it has remained one of Glasgow's most baffling unsolved murders.

Twenty-four-year-old Rangers fan Derek Sheerin had been found strangled and half naked in waste ground at the back of a well-known Celtic supporters social club in the East End of Glasgow on September 26, 1994.

The murder scene was also close to the Barrowfield training complex where the club's first team players then trained before games.

Derek had stayed with mum Maureen and stepdad Henry in Easterhouse the previous Saturday night.

Normally he lived with his sister Diane on London Road across the road from the social club.

But there had been a change of plans and he had given up his bed there for a pal Philip Morrison.

When his body was found on the Monday, police discovered he had been strangled with his belt and watch and cash stolen.

They wondered at first if it had been a violent robbery.

But detectives realised that there may have been more to the crime – given that some of the victim's clothing had been removed.

Could this have been a sexual encounter that had gone horribly wrong?

But with whom and how had they met?

Detectives speculated that Derek may have been gay though he had never come out to his family.

The last sighting of him was on the Sunday evening around 6.30pm in nearby Glenisla Street but nothing after that.

Could he have met someone later that night, possibly in the city centre, and then be taken to the remote spot?

But officers also wondered if the murder motive lay closer to home.

Was the person responsible someone Derek knew and trusted?

At the time both the police and the victim's family made numerous appeals for information, but no one came forward.

The murder had probably happened when the supporters club was closed, and most people were safely tucked up in their beds.

There was no CCTV in the area to pick up his last movements.

The case was eventually wound up and put into cold storage.

In 2001, police investigated the possibility that Derek had been a victim of notorious murderer William Beggs. At the time Beggs was serving a life sentence for killing and dismembering Barry Wallace, 18, in Kilmarnock in 1999.

Doing the original investigation forensic experts had discovered the blood of 17 different men in the killer's Kilmarnock home. Checks were made, but there were no matches to Derek.

In 2015 detectives did a second cold case review using the latest in DNA technology.

They found a match on his clothing including the belt used to strangle him.

The man in question was former pal Philip Morrison, now 39, who was living in Derry in Northern Ireland.

Morrison was arrested and taken back to Scotland where he appeared at Glasgow Sheriff Court in October 2015 charged with his murder.

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Eighteen months later, in March 2017, he stood trial at the High Court in Glasgow.

He was accused of struggling with Derek, compressing his neck with a belt and his hands, murdering him and robbing him of a watch, tobacco and £20 in cash.

The jury was shown crime scene photographs of Derek lying half naked with paper and a diary strewn beside him.

His sister Jacqueline Marshall, now 51, said the last time she saw her brother was around lunchtime on the Sunday. She had met Morrison for the first time at their mother's home in Easterhouse the previous day.

Asked if she knew her brother was gay, she replied: "No … I had an idea."

Derek Ogg, representing Morrison, said: "Attitudes in 1994 were a bit different towards gay people."

Jacqueline replied: "Yes."

The QC added: "Could Derek have had a life that was secret?"

She replied: "I don't know. He might have done."

Jacqueline then told the court about her first encounter with the accused.

She added: "Derek introduced me to him and asked if he could stay the night at my house.

"I wasn't sure of Philip, but because he was Derek's friend, I thought he was harmless."

Jacqueline thought her brother had spent the night at their mother's house.

Derek then returned on the Sunday morning to collect his friend Morrison and they left around lunchtime.

Prosecutor Iain McSporran asked her: "Is that the last time you saw your brother?"

She replied: "Yes, it was."

She said her brother appeared happy enough, she had words with him about 'dumping' his friend on her and she added: "He just laughed."

The court was told that on the Monday, she was contacted by her sister Diane who was worried because a body had been found and she could not contact Derek.

Jacqueline added: "The area had been cordoned off and police weren't giving any information. Derek was supposed to stay at my sister's house on the Sunday evening, but he wasn't there."

The court was told that another sister Elaine phoned the police, and both she and Jacqueline were taken to the mortuary where they identified their brother's body.

Another woman described how she found a body as she and two friends went to watch the Celtic players train.

Kerry Gillespie, now 36, said that she was a 14-year-old schoolgirl when she discovered the body of Derek lying on waste ground behind the Celtic supporters social club, close to the stadium.

Kerry said she and her friends were walking with her in front when she spotted the body.

Mr McSporran asked Kerry: "What did you do when you saw the body?"

She replied: "I screamed and ran back."

Kerry approached two men who were walking down the path from London Road towards the River Clyde, who alerted the police.

When Constable James Grayson arrived, he put Kerry and her friends in the back of his van, before walking down to where the body lay.

The jury was told that he had since died. Instead, his statement was read out in court.

It described how the victim's trousers were down and a black leather belt around his neck.

Forensic scientist Dr Nighean Stevenson told the jury there had been huge advances in DNA technology since Derek's death, and the black leather belt was re-examined as part of the 2015 cold case investigation.

She said DNA matching both Morrison and Derek was found.

Dr Stevenson said one possibility was that the belt had been used as a ligature, and that Morrison had strangled Derek.

But she also said it was just as possible that Morrison had borrowed Derek's belt and had been wearing it, she could not say which of the two scenarios were more likely.

The court also heard that DNA from an unknown man was found on Derek's face and hands, his denim jacket and the inside of his t-shirt. No matches for it were found at the time or since on any UK databases.

Mr Ogg asked: "The DNA of this unknown male is all over the body?"

Dr Stevenson replied: "Yes."

It was also revealed the bag containing the belt had been left open when it was first given to scientists to examine in 1994.

Morrison's defence counsel asked the doctor if that fact rang alarm bells, and she replied “it does”.

When asked if it was "bad practice" for the bag to be open, she said an item wouldn't be accepted for DNA testing today if it wasn't properly packaged.

Then in a dramatic development Mr McSporran told the court they had decided to drop the murder charge against Morrison.

DNA was a crucial part of the Crown case against him. Given that the bag was open and could have been contaminated, it meant they could no longer proceed against him.

Trial judge Lady Rae then told the Derry man: "I find you not guilty. You are free to go."

Police Scotland is still committed to getting justice for Derek's family and such cases are never closed.

It says his murder is still subject to review and any new information will be investigated.

Detective Inspector Stuart Grainger added: “The passage of time is no barrier to the investigation of unresolved homicide cases.”

Mystery still surrounds the identity of the unknown man whose DNA was found on Derek.

Was he the real assailant or just someone the victim had previously and innocently come into contact with.

If Morrison didn't kill Derek, then who did?