Colin Howell's ex-wife has revealed that he threatened to commit suicide when she forced him to confess to police about the murders of his first wife Lesley and the husband of his ex-lover Hazel Stewart.
Kyle Jorgensen, an American, convinced the dentist to own up after he was swindled out of their life savings, admitted indecently assaulting sedated patients at his surgery and cheated on her with another woman for a second time in their marriage.
Howell, a religious fanatic who became addicted to online pornography, talked several times about taking his life before he eventually agreed to hand himself over to detectives after making his shock admissions to church elders at their house outside Castlerock, Co Londonderry, according to his ex-wife.
Howell first made his sensational admission of the murders to her in the summer of 1998, just months after the birth of the first of their five children, Erik, who suffered digestive problems.
Ms Jorgensen also needed hospital treatment for an infection and although Howell was on the verge of handing himself in, she alleged that he convinced her to stay quiet and stick with him for the sake of the family.
Just after Howell confessed to police in January 2009 how he gassed his wife and police officer Trevor Buchanan and then stage-managed the deaths in May 1991 to make them look like suicides, police twice questioned Ms Jorgensen about how, why, when, where and what her husband told her just over a decade earlier as they sat in the lounge of their luxury home.
But almost three years after police submitted a file, the office of the Public Prosecution Service in Belfast has yet to decide if she should face any legal action over her failure to go to the authorities. A police spokesman said: "The investigation is ongoing."
Howell, 52, is serving a minimum 21 years. His former lover Stewart, 48, who remarried police Chief Superintendent David Stewart, was sentenced to 18 years after she was found guilty for her part in the two murders by a Crown Court jury in Coleraine last March.
It emerged that she has been refused leave to appeal against the conviction, but that decision could be challenged at the Court of Appeal in Belfast.
A highly critical report by officers of the Northern Ireland Police Ombudsman Al Hutchinson, who investigated the deeply flawed initial police inquiry which allowed Howell and Stewart to get away with murder for 18 years, is due to be published early next month.