It was 1982 and an evil sex predator had been stalking the streets of Glasgow for the last four years.

He would lure girls as young as six into tenement closes then rape and sexually assault them.

The mystery attacker would always grab his victims from behind so they would never see his face.

Sometimes the fiend would strike twice on the same day.

Since his reign of terror began in 1978 he'd claimed at least ten victims but more were to follow.

That year every cop in the city was on the lookout for the monster who showed no mercy or pity for his victims.

Appeals had been made in the press and a photofit of their suspect had been issued as the attacks mounted.

On April 24 a ten-year-old girl was raped in a tenement close in Langside Road in Govanhill on the South Side of Glasgow.

The latest case was investigated by a small team of cops based in nearby Gorbals Police Office led by Detective Inspector Joe Jackson.

As was to be expected the 10-year-old was left deeply traumatised and damaged by the attack.

Now retired Joe told the Glasgow Times: "That was the first one that came to my attention and that poor wee girl was very badly assaulted.

"At the time all the rapes were being widely reported but there wasn't a lot of information to go on because of the age of the victims.

"I gathered all the cases from across Glasgow and realise there was one link - they were all happening at weekends.

"He was going to work on the Saturday morning and then looking for victims afterwards.

"I told all my detectives that they were now on standby at weekends because that was when he was most likely to strike."

In fact the sexual predator did strike the following weekend and again in Govanhill.

But when he tried to attack another ten year old, she alerted two women and he fled.

An hour later, angered by his failure, he raped a child in Finnieston in the city's west end.

However thanks to the second ten year old victim the police now had a proper description of their prime suspect.

She spoke of a small man with green hair and ears and with marks on his shoes but not dirty marks.

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The suspect she later picked out from a police mugshot book was Angus Robertson Sinclair who detectives discovered had raped and strangled his seven-year old girl neighbour Catherine Reehill in 1961.

He was sentenced to 10 years in prison for culpable homicide and a psychiatrist's report warned Sinclair would remain a "very dangerous sexual case".

The officers didn't know at the time but Sinclair had also murdered two young women in Edinburgh and another in Glasgow.

Thanks to the ten year old's evidence he was arrested a few days later at his home in Nitshill on the south-side.

It would prove to be the last ever day of freedom for the 35-year-old.

Joe added:"When we brought Sinclair in for questioning we noticed he had green specks of paint in his hair and inside his ears.

"He was in fact a painter and decorator and shoes were covered in paint spots exactly as the girl had described."

However when detectives quizzed him about the attacks Sinclair said nothing.

That posed a problem as the detectives only had the statements of his traumatised young victims to rely on.

Joe came up with the novel idea of bringing in Sinclair's wife, a psychiatric nurse, to sit through the interviews.

As he read over the 13 charges, with his spouse sitting next to him, Sinclair began to open up about the Glasgow attacks.

When asked about the rape of an eight-year-old Turkish girl in a close in Anderston on August 15, 1978, at knifepoint, he replied: "Yes that's right, that was me. I remember that wee lassie."

On the sexually assault of an eight-year old girl in Dennistoun on November 3, 1978, he replied: "I don't honestly remember, but it sounds like me. Yes that was me."

And on attacking the 10-year-old in Govanhill on April 24, he said: "If that's it, then I probably did it."

Sinclair also challenged Jackson: "If you can find out where and when, I'll tell you whether I did them or not."

He did not volunteer any other information, other than to say:"I've done so many I cannae remember them all. I could have done 50, I just don't know."

Jackson added:"Sinclair appeared to be living a normal life, he was married with a kid in a decent house."

"I had him for three days at the Gorbals in front of his wife.

"It was quite risky because generally wives will support their husbands.

"However she was horrified what he was doing to young kids.

"She was saying during the interviews: 'Angus talk to the man, tell him what you have done.'"

Joe also believes Sinclair was a responsible for a rape of a young boy on Halloween night the previous year in Allison Street, Govanhill. His victim had been dressed as a girl.

The former police chief added:"That was the only one Sinclair would not admit to probably because he had a young son of his own at the same age.

"I thought to myself this guy has done more but the victims either didn't tell their parents or their parents failed to inform the police."

Sinclair eventually confessed to 13 charges of rape and indecent assaults against children, aged six to 14, between 1978 and 1982.

He appeared at the High Court in Edinburgh later that year and was given life with the recommendation he serve at least 30 years.

Joe added:"Sinclair could not stop himself and was driven by his sexual habits.

"He asked to be medically castrated in the hope it would get his sentence down.

"The judge realised what a danger he was to the public with the sentence he handed out.

"Sinclair admitted the attacks without a hint of remorse and recalled them like run-of-the- mill events."

In the following years advances in forensic science resulted in justice for his other victims and their families.

In November 1978, Mary Gallagher, had been found murdered in Springburn on the north side of the city.

The crime remained unsolved for 23 years until a cold case review using DNA identified Sinclair as the killer, who then got another life sentence in 2001.

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The previous year Helen Scott and Christine Eadie, both 17, were murdered after a night out in the World's End pub in Edinburgh's High Street. Their bodies were later found dumped 16 mies away in in East Lothian.

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Again DNA evidence from the crime scene linked Sinclair to the two victims.

In 2007 he appeared at the High Court in Edinburgh on the double murder charge but the trial collapsed because of a lack of evidence.

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Seven years later he became the first person in Scotland to be re-tried for the same crime on new double jeopardy rules.

He was found guilty of Helen and Christine's double murder and sentenced to a minimum of 37 years in jail at the High Court in Livingston - the longest term in Scottish legal history.

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Sinclair is also believed responsible for the unsolved murders of Anna Kenny, 20, Hilda McAuley, 36, and Agnes Cooney, above, 23 in Glasgow in 1977.

In March 2019 he died in his cell at Glenochil Prison in Clackmananshire from natural causes at the age of 73.

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By this time he was incontinent and bedbound following a series of strokes.

Thanks to Joe and his team Sinclair had been off the streets for 37 years.

After his 1982 arrest Jackson sent a memo to every force in Scotland recommending he should be investigated for any outstanding sex crimes. However, his advice was ignored.

Jackson rose to become head of Strathclyde Serious Crime Squad and retired in 1992 at the rank of Detective Superintendent.

Now 80 years old he says the arrest and conviction of Sinclair was one of his biggest achievements as a police officer.

Mr Jackson said:"It gave me great personal satisfaction to put him behind bars as it meant Sinclair was no longer free to commit horrendous crimes against vulnerable members of society."