Mark Nash, who was sentenced last night to two life sentences for murdering two people in Co Roscommon, also admitted murdering two elderly women patients of Grangegorman Psychiatric Hospital, Dublin in March last year.
After Nash was arrested in Galway on August 17th last year for the Doyle murders, he told gardai he had previously killed two women in Dublin. He also wrote two letters saying the same thing.
While being interviewed in Mill Street Garda station in Galway about the murder of Mr Carl and Mrs Catherine Doyle at their Co Roscommon home two days earlier, he made a detailed statement about the murders of Ms Sylvia Shields (59) and Ms Mary Callinan (61) as they slept in their beds on March 6th/7th, 1997.
Nash's statement contained specific details about the murders which could have come only from someone familiar with the circumstances of the Grangegorman killings or who knew details from the Garda investigation into them.
The gardai in Galway who questioned Nash about the Roscommon murders were puzzled about the second confession, and passed details on to gardai in Dublin. By that stage the Dublin gardai had charged an innocent man, Mr Dean Lyons, with the Grangegorman murders. Mr Lyons had been arrested at a hostel for the homeless in Dublin on July 27th last year, two weeks before the murders in Roscommon. The Director of Public Prosecutions later withdrew the murder charges against Mr Lyons.
A subsequent investigation showed striking similarities between the Roscommon and Grangegorman murders.
All the victims received multiple stab wounds of great force, penetrating right through the bodies in some instances. The murderer, in both cases, went into the kitchens of the respective houses and collected weapons, carving knives and forks from cutlery drawers.
Nash has also been questioned while in Mountjoy by British police about the murder of an elderly woman at her home in Huddersfield in the spring of 1996.