The man accused of murdering dog walker Jean Campbell with a heavy metal lead was today cleared of involvement in her death.

At the High Court in Glasgow judge Lord Matthews acquitted 21-year-old Paul Ward after hearing an examination of facts into her murder.

MrWard, who is suffering from a psychotic illness, was due to stand trial, but he was deemed unfit to do so. He denied murdering Mrs Campbell.

The prosecution claimed Mr Ward killed Mrs Campbell because he was an animal lover and hated the way she treated her German Shepherd Kai.

Lord Matthews said: "A great many hours of work were put into this case by dedicated policemen, including authorised surveillance of the accused's home, but the result of all of it, is in my opinion at least, a weak Crown case.

"There was proof of an a possible, albeit tenuous motive. The accused potentially had the opportunity. There are a number of suspicious circumstances in this case and the accused might have committed the acts referred to in the indictment, but that is not the test."

Lord Matthews said that the Crown case did not convince him beyond reasonable doubt that Mr Ward was Mrs Campbell's assailant.

He added: "I appreciate that what I have said might not find favour with the family and friends of Mrs Campbell.

"In this day and age what I have to say may not be the final word on the matter. No doubt the matter can be revisited if compelling new evidence emerges. However, I can only proceed on the evidence presented to me."

Mrs Campbell's widower John looked "shellshocked" as the judge's determination was given and had to be comforted by family members.

Lord Matthews ordered that Mr Ward should be detained at the State Hospital for six hours to allow him to be examined and appropriate medical treatment organised for him.

Defence QC Donald Findlay said: "It is clear this young man is likely to require treatment for a considerable period of time."

During the court hearing prosecutors alleged that Mr Ward attacked Mrs Campbell in Cranhill Park, Glasgow, on December 13, 2013 with a dog lead.

Mrs Campbell, who was 4ft 11in and weighed six stones, was ferociously whipped with the dog lead in a sustained assault in which she suffered 11 broken ribs, a fractured leg, bruising to her head and neck and a brain injury.

Her body was found around 7.40am the following morning by her husband of 35 years John, 56, who came home from nightshift to find all the lights on and no-one at home. He went looking for her and discovered her body lying in the park. She was wearing a pyjama top and a black coat. Her pyjama bottoms and a pair of flip flops were lying nearby.

A massive murder hunt was launched to try to find her killer and an appeal for information was made on Crimewatch.

Mrs Campbell was last seen alive on footage from a CCTV camera taken at 10.30pm. She and her German Shepherd dog Kai were walking along Bellrock Street towards Cranhill Park. Prosecutors and detectives believe she met her killer in the park and was attacked around 11pm.

The court heard that Mrs Campbell sometimes shouted at and hit her dog, which was too powerful for her to control.

Advocate depute Alex Prentice QC said: "Mr Ward said words to the effect: 'I hate her. 'She is always hitting the dog. How would she like it if I did that to her.'"

Suspicion first fell on Ward after inquiries revealed that he was out walking that night around the time Mrs Campbell is believed to have been attacked.

Neighbour Yvonne Leyden, 54, whose living room window faced on to Cranhill Park told of hearing screams and a dog barking around 11pm. Minutes later she said she opened the door to Mr Ward, who was a friend of her son Thomas Leyden, 24. Ward had been at the Leyden's home earlier that night, then went home where he had spaghetti bolognaise and a glass of wine, before returning there.

Mrs Leyden said Ward arrived minutes after she heard the scream and was was out of breath, but the court heard this was not unusual as he ran everywhere CCTV footage played in court showed Mr Ward walking towards the communal entrance to number 5 Crowlin Crescent, where the Leyden's lived at 11.06pm. But, crucially there was no footage to show where Mr Ward had come from. He could have walked through the park and encountered Mrs Campbell, but equally he could have gone a number of other ways to get to Crowlin Crescent.

No forensic evidence linking Mr Ward to the assault on Mrs Campbell, who had bravely fought for her life against her attacker and had defensive injuries to her hands and arms, was found. He also had no signs of cuts or scratches on him.

Mrs Leyden, her son and his then girlfriend Shelby McPhail, 19, said that when Mr Ward returned just after 11pm he was his normal self and there was no sign of blood or mud on his clothing. In fact Miss McPhail insisted that Mr Ward was with them when Mrs Leyden spoke to them about hearing screaming.

After Mrs Campbell's death when rumours began to link Mr Ward to the killing, he denied having anything to do with it. Police got permission to bug his house for four weeks in the belief that Mr Ward would utter something incriminating - but he never did. He also denied the murder when arrested by police, telling detectives: "It wasn't me."

While on remand in Barlinnie Prison in August last year Mr Ward told his mother during a phone conversation: "What happened to that woman might have been me." He went on: "I've been hearing stuff in my head. I think I might have hit her once."

But, Lord Matthews said he discounted this alleged confession because the taped conversation happened four days after Mr Ward was diagnosed as having a psychotic illness.

The prosecution dismissed any suggestion of a sexual motive for the murder. But defence QC claimed that given Mrs Campbell's pyjama bottoms had been removed and she had an unexplained injury to her private parts the attack could have been sexually motivated.

Mrs Campbell's family declined to comment as they left the court.