The Court of Appeal has upheld multiple murderer Mark Nash's conviction for the killing of two women in Dublin.

Nash was found guilty in 2015 of murdering Sylvia Sheils, 59, and Mary Callanan, 61, between 6 and 7 March 1997.

The women’s bodies were found in sheltered accommodation in Grangegorman.

The 44-year-old, who is originally from England but has last addresses at Prussia Street and Clonliffe Road in Dublin, had pleaded not guilty at the Central Criminal Court to the murders.

A Central Criminal Court jury found Nash unanimously guilty after deliberating for four hours following a 48-day trial and he was given the mandatory life sentence by Mr Justice Carroll Moran on 20 April 2015.

Nash had already been serving life since October 1998 for murdering two people in Ballintober, Castlerea, Co Roscommon and leaving a woman seriously injured in mid-August 1997.

The four murders were committed within the space of five months.

Opening an appeal against his conviction for the Grangegorman murders, Nash's lead senior counsel, Hugh Hartnett SC, told the Court of Appeal that it was an "extraordinary and unusual case" because another man, the late Dean Lyons, had "confessed".

A short time later, while Nash was in detention on foot of the Roscommon double killing, he admitted to having carried out the Grangegorman murders five months earlier.

Mr Lyons died in 2000 and a jacket, which had been seized from Nash's home during the investigation in the 1990s, was tested and nothing of probative value was found.

Nearly ten years later, and with advances in science, DNA was found around the button threads of Nash's jacket and the DPP decided to prosecute.

Mr Hartnett said the two main planks to the prosecution's case were the admissions made by Nash and the DNA evidence.

Dismissing Nash's appeal against conviction today, Mr Justice Alan Mahon said it had been a lengthy and complex trial, stretching over four months in 2015.

Mr Justice Mahon, who sat with Mr Justice John Edwards and Mr Justice Michael White, said the various appeal grounds had been considered in detail, particularly issues relating to the admissions of Nash and the scientific and forensic evidence.

However, he said no grounds of appeal were upheld by the court and "accordingly we must dismiss the appeal".

Nash was not in court for the delivery of the judgment.