NOTORIOUS British serial killer Mark Nash has appealed against his convictions for a brutal double murder in Ireland in March 1997.
Nash, who is originally from England, has been imprisoned in Ireland since 1998 when he was found guilty of the separate killings of Irish couple Carl and Catherine Doyle in their Roscommon home on August 16, 1997.
Then, two years ago, the 44-year-old was further found guilty of the March 1997 murders of Sylvia Shiels and Mary Callanan in Grangegorman, Dublin.
Their mutilated bodies were found in sheltered accommodation in the north inner city of the Irish capital five months before the Roscommon murders.
Opening his appeal on Monday, Nash told Dublin's Court of Appeal that there were a number of issues about the way his 2015 trial was run.
The killer’s barrister Hugh Hartnett described his case as "unusual and extraordinary" because another man named Dean Lyons admitted killing the women before his death in 2000.
The Garda investigation into the murders of Ms Shiels and Ms Callanan stalled in 2009 when a jacket with Nash’s DNA was examined in the same lab as other articles of evidence.
Nash’s appeal is focused on the possibility that the jacket was cross-contaminated, as well as the way the judge advised the jury to deal with the admissions made by Dean Lyons.
Experts in Nash's trial two years ago told the jury there was a possibility the jacket had indeed been cross-contaminated.
Nevertheless, Nash was sentenced to life for the murders despite the potential contamination of evidence and admissions made by Mr Lyons.
Mr Nash's hearing continues before the three-judge Court of Appeal today in Dublin.
A final decision on his appeal is due to be made on Wednesday.