A dentist was sentenced to life imprisonment today for the murders of his wife and his ex-lover's husband who were poisoned by carbon monoxide fumes almost 20 years ago.
Dr Colin Howell, 51, changed his plea at Belfast Crown Court and admitted the 1991 killings which police first thought was a suicide pact.
He pleaded guilty to murdering his wife and mother-of-four Lesley, 31, and Pc Trevor Buchanan, 32, whose bodies were discovered in a fume-filled car in the seaside town of Castlerock, Co Londonderry.
Howell, also from Castlerock, had denied the two charges since his arrest last year, but owned up to the double murder when he stood in the dock as relatives of his victims looked on.
His former lover, Hazel Stewart, who was married to Pc Buchanan at the time, is due to stand trial for the two murders in Coleraine, Co Londonderry, next week.
Mother-of-two Mrs Stewart, 47, from Ballystrone Road, Coleraine - she later remarried - was in the Laganside court building today but was not in Court 12 as her co-accused changed his plea.
Howell, dressed in a grey suit, white shirt and tie, spoke only three times during the 10-minute hearing - once to confirm his name and to answer guilty to each charge in turn.
Judge Mr Justice Anthony Hart told him that he would be jailed for life with his minimum term to be determined at a later hearing.
"You have pleaded guilty to two charges of murder.
"The only sentence the law allows is one of life imprisonment which I now sentence you," he said.
At the time, it was believed the two victims had taken their own lives because of depression over an affair between Howell and Stewart.
But detectives reopened the investigation in January last year when they interviewed Howell.
Howell and his co-accused, as well as their partners, were all members of Coleraine Baptist Church at the time of the deaths. But when he was arrested last year, he was a member of a north Antrim-based church group called the Barn Christian Fellowship.
Stewart had been attending Portstewart Baptist Church with her second husband, former police Chief Superintendent David Stewart, once a staff officer to ex-Royal Ulster Constabulary Chief Constable Sir Hugh Annesley.
As well as the two murders, Howell was also questioned about the death of his father-in-law Harry Clarke, 69, an ex-Royal Marine regimental Sergeant Major and company director, who collapsed and died at Howell's home 12 days before the bodies of his daughter and Constable Buchanan were found.
Howell categorically denied he was responsible. Mr Clarke, who had been suffering from flu and staying in the Howell's spare bedroom, is believed to have had a heart attack in the kitchen of the house at Knocklayde Park, Coleraine.
He was found when the Howells returned home from a night out. Their four children were being looked after by a babysitter. After leaving the Army he lived in Scotland, Dublin and then Hillsborough, Co Down, before buying a house on the north Coast.
It was in Mr Clarke's garage behind his home in Castlerock - number six in a row of houses, high above the village, known as The Apostles - that the bodies were found by two members of Coleraine Baptist Church, one of them an off duty police officer.
The ignition had been switched on but by the time the missing pair were discovered, the car engine had stopped running.
Pc Buchanan, wearing denim jeans and a sweater, was sitting slumped low in the front driver's seat of Howell's seven-seater Renault Savanna estate, his right knee in the joint of an open door with its window down.
Mrs Howell was lying on her back in the boot wearing the headset of her personal stereo in which a tape recording of her favourite singer and composer had been inserted. She was wearing dark-coloured leggings, a blue T-shirt and white trainers.
Three framed family photographs - one of herself in her student nurse's uniform on the day she graduated, one of her brother and one of her father and mother May, who died in 1986 - were lying beside her. One end of a vacuum cleaner hose had been connected to the car's exhaust pipe and the other placed close to her head. The car's boot door had been pulled down.
A year after the police launched an investigation, a coroner's court inquest said the deaths were suicides, both victims having been poisoned by carbon monoxide fumes.
Mrs Howell, born in Plymouth and a former award winning nurse at the Royal Victoria Hospital in Belfast, died on her son Daniel's second birthday.
He was in court today - sitting in the public gallery with his sister Lauren and the late Mrs Howell's only brother, Chris, a hospital anaesthetist in Blackpool - to hear his father plead guilty to his mother's murder and the murder of Pc Buchanan, a scenes of crime officer with the RUC.
Members of Pc Buchanan's family, including his two sisters, Valerie and Malva, and his brothers Gordon, Victor, Raymond, Robert and Jackie, also took their seats in the public gallery for the brief hearing. A spokesman for the family said they were not prepared to make any comment.
Howell's wife Kyle, 44, a US divorcee, has moved to Florida with the couple's five children and has filed for divorce. She was not in court today.
She met Howell in December 1996 when she was a student doing a degree in Irish history at the University of Ulster in Coleraine and living in neighbouring Portstewart, Co Londonderry, with her two children from her first marriage. She married in May the following year and went on to have five children with him.
But soon after Howell's arrest she left Northern Ireland and the couple's luxury home at Glebe Road, Castlerock, where her husband had been detained by investigating officers. He had been living away from the house, staying at a caravan site in the village.
Mrs Howell's US legal representative Dennis Avery of law firm Avery, Whigham and Winesett, in Fort Myers, said: "I have no authorisation to make any comment."
Howell's eldest son Matthew, 22, was killed when he slipped and fell 40ft down a stairwell at an apartment block in St Petersburg, Russia, in April 2006. He had been a student at St Andrews University and was on an overseas semester as part of his degree course in Russian, Spanish and international studies.
The Matthew Howell Dissertation prize in international relations is awarded by the university each year.
Howell has already admitted indecent assault charges against three of his patients in April and July 2008 at his clinic in Ballymoney.
Stewart's trial is due to begin next week at Coleraine Courthouse. The jury is due to be chosen and sworn in on Wednesday and Thursday.