NEILSTON sex offender who preyed on four victims aged between eight and 19 over a 38-year-period is facing jail.

William Hislop, 53, targeted the boy and three girls, who are all now adults and can't be named for legal reasons, between 1977 and 2015.

Police found out in 2004 that he abused his second and third victims.

But it was ruled there was insufficient evidence to prosecute him over the offences - and he was therefore free to abuse his fourth victim, who is disabled, in March last year.

The details emerged today when Hislop appeared in the dock at Paisley Sheriff Court to admit his guilt over the offences.

He pleaded guilty to four charges against him and could be jailed for as long as five years for the crimes.

He abused his first victim between 1978 and 1980, when the boy was aged between eight and 10, at an address in Renfrew.

Procurator fiscal depute Scot Dignan told the court that Hislop, who was 16 or 17 at the time, went in to the double bed the boy was in and abused him.

He abused his second victim between 1977 and 1980, when she was aged between 12 and 14, at the same address.

His third victim was abused between 1994 and 1995 at another address in the burgh town.

He told the nine-year-old he had a surprise for her before entering her bedroom and watching her getting changed before performing a sex act on her.

Embarrassed at what had happened to her, she went to a friend's house and told her what Hislop had done.

But she was unable to tell her mum what had happened and ended up writing it in a letter.

The letter was later found by her mum, who therefore found out what had happened, and the police were informed.

Dignan explained: "This was reported in 2004 and was initially investigated but there was insufficient evidence to proceed.

"He was interviewed on February 19, 2004.

"He was interviewed again in 2011 but, as indicated, there was insufficient evidence to proceed as these times."

As Hislop was not prosecuted in 2004 or 2011 he was free to abuse his fourth victim in March last year at his home in Neilston.

The court heard he was drinking with the 19-year-old, who suffers from dyslexia, dyspraxia and autism, and her boyfriend and struck after her boyfriend had fallen asleep.

He asked her for a cuddle before abusing her as she cried and told him to stop.

She told her boyfriend what had happened the following morning and the police were contacted a couple of days later.

The 2015 assault meant there was now enough evidence to prosecute Hislop over the abuse of the other two women in the '70s and '90s.

And as part of their investigation police officers discovered he had also abused the boy in the late '70s.

Long-haired Hislop, who arrived at court wearing a tassled leather jacket and leather flat cap, pulled faces in the dock as the details of his disgusting crimes were read to the court.

As Sheriff Seith Ireland released Hislop on bail and deferred sentence until next month, he said: "You have pleaded guilty to serious charges but as the law requires I must get specialist reports.

"These are extremely serious matters."

Hislop was also placed on the Sex Offenders' Register, with the length of his placement on the register to be decided when he returns to court next month.