A "spectacular breakthrough" led to the DNA of two women, found dead at their sheltered accommodation 18 years ago, being found on the jacket of a man on trial accused of their murder, a trial has heard.
Mark Nash (42) has pleaded not guilty at the Central Criminal Court to the murder of Sylvia Shields (60) and Mary Callanan (61).
Mr Nash is charged with the murders of the women, who lived in a house attached to St Brendan's Psychiatric Hospital in Grangegorman, Dublin 7 between March 6-7, 1997.
Opening the prosecution case, Brendan Grehan SC told the jury the fact it was 18 years ago was "a factor in this case".
Mr Grehan said the offences "occurred quite a considerable time ago and for that reason you will not hear from some witnesses, who have in fact died".
He also outlined there would be "a reference to a Dean Lyons ,who is since deceased".
Mr Grehan said that a bloodstain found on a lower button on the sleeve of Mr Nash's jacket in 1997 could not be developed as a DNA sample.
However, the court heard that in July 2009 a "spectacular breakthrough" was made with new tests. DNA from both women was found on the black velvet, stripey jacket.
The jury was told that Mr Nash had confessed to gardaí that he had carried out the Grangegorman murders, after being charged with the double murder of Carl and Catherine Doyle at their Roscommon home in August 1997.
On August 16, 1997, Mr Grehan said, Mr Nash was arrested outside Galway city in relation to the Roscommon murders.
While in Mill Street Garda Station, the court heard that Mr Nash said he had committed the Grangegorman murders.
But Mr Grehan said that at the time, gardaí had no interest.
"As far as they were aware, the crimes had been solved and a Dean Lyons had confessed to these murders on July 26. He had been charged and was in custody for these murders."
However, Dublin man Mr Lyons was later exonerated.
Mr Nash - who has last addresses at Prussia Street and Clonliffe Road in Dublin -subsequently withdrew his admissions and was shocked his statement was taken seriously, as he said he was "in serious mental anger and distress". Mr Grehan told the court: "He said he would like to state for the record, he had nothing to do with (the Grangegorman) murders ... he would have taken the rap for killing the Pope."
The jury under Mr Justice Carroll Moran also heard about the "badly-mutilated bodies" which were left "partially clad" after being abused using serrated blades, a knife, a large carving knife and a carving fork.
These implements are believed to have originated from the kitchen of the house in Grangegorman, which was demolished in order to make way for the new DIT.
Ms Shields had at "least 17 separate injuries afflicted to her body, some 10 separate wounds to head and neck area".
Ms Callanan had a "severe facial and knife wound through her mouth and lips, her throat been severed with 36 strokes".
Both had also sustained serious genital injuries.
The trial continues.