A former soldier who was convicted last week of raping and killing a schoolgirl 40 years ago has now admitted sexually assaulting another teenager last year.
Stephen Hough, 58, let an innocent man go to jail and denied any involvement in the death of Janet Commins, 15, in Flint in 1976 during his three-week trial at Mold Crown Court.
He was cleared by the jury last week of murder, but convicted of her manslaughter, rape and buggery.
Jurors were told of a billion-to-one match of his DNA profile to semen left at the crime scene and stored for four decades.
But they were not told police only made the DNA match after he was arrested in February last year for sexually assaulting another girl, aged 15, and swabs were taken.
Hough, a father-of-two, separated from his second wife and working as a lorry driver after being thrown out of the Army for attacking and strangling another woman in the 1980s, was due to go on trial for the latest offences in September.
Instead, he was sentenced to 12 years in jail for his attack on Janet, then after a short adjournment returned to court to plead not guilty to rape, but admitted sexual assault by touching the youngster in February last year.
He plied his victim with drink before leaving her bruised, with his semen and DNA later recovered from her body and underwear.
The girl, as a victim of a sexual offence, cannot be identified.
In a victim impact statement, she told the court: "Thinking about it makes me feel sick.
"Having heard the devastation of what Stephen Hough has done previously, I feel fortunate things were not worse."
Mr Justice Clive Lewis sentenced Hough to three years for the sexual assault on the girl, to be served consecutive to his 12-year sentence. He will be eligible for parole after half of the 15-year sentence.
Passing sentence on Hough for the second time in a day, the judge said: "Over the last 40 years, you have killed someone, raped and buggered her and also been found guilty of grievous bodily harm on another woman. You have shown no remorse."
Janet Commins family described the defendant as a "sexual predator".
Outside, Derek Ierston, who identified his niece's body, spoke on behalf of the family, saying they were "very, very disappointed" with the sentence.
He added: "But the law is such you have to accept it, whether you like it or not.
"I think the judge is very, very good but his hands are tied."
Hough hid his guilt for killing Janet while another man, Noel Jones, was jailed for her manslaughter in 1976.
North Wales Police is now under investigation by the Independent Police Complaints Commission (IPCC) over how it handled the 1976 investigation at the time of Janet's death.
Hough was 16 when he attacked Janet, who was choked as she was repeatedly and violently raped.
But within days, police had arrested Noel Jones, 18 at the time, an illiterate scrap dealer from the gypsy community, who eventually pleaded guilty to manslaughter and was jailed.
Mr Jones told Hough's trial he was browbeaten and "coerced" into making a false confession by detectives.
Janet's family described the 1976 police investigation as "shoddy", with officers having "no interest" in investigating once they arrested Noel Jones.
Janet, an only child, disappeared on January 7 1976 after leaving a note for her parents Eileen and Edward, saying she would return to their home in Flint at around 8.30pm that night.
Described as a slightly timid and shy girl, she visited friends at the local swimming pool but vanished on her way back.
Four days later, her body was found by children playing hide and seek in a thicket near Gwynedd School in Flint.
Semen and cell samples were taken from her body, preserved and stored.
As part of the large-scale murder inquiry, all local young men up to the age of 22 were visited by police and asked to account for their movements on the night Janet disappeared.
Hough, a keen rugby and ice hockey player and "very fit young man", told police he had been stealing petrol on the night and was fined £5.
Noel Jones told the jury he was picked up by police outside a pub the day after Janet's body was found, questioned for two days without a solicitor and made a "scapegoat" by the force after signing a confession he could not even read.
He later served six years of a 12-year sentence for manslaughter.
Mr Jones, 59, told the jury the conviction ruined his life as he was attacked while inside jail and ostracised by friends and family on the outside.
Last year, he was visited again by police "out of the blue" and, to his "shock and relief", told the case had been re-opened.
Meanwhile, Hough served with the British Army in Germany where he was jailed for five years for grievous body harm.
He attacked a hotel receptionist, dragged her into a toilet cubicle and was strangling her until he was disturbed. He denied it until forensic evidence linked him to the crime scene.
He was demoted and dismissed from the forces and returned to the UK.
Last year, police took a sample of Hough's DNA in circumstances "that are of no significance to this case", the jury heard, making the billion-to-one match with the profile from the crime scene.