DNA was found on murder accused's jacket, court told
DNA profiles from two women killed in Grangegorman nearly 20 years ago were found on a jacket belonging to murder accused Mark Nash in 2009, a jury has heard.
Mark Nash (42) who has last addresses at Prussia Street and Clonliffe Road in Dublin, has pleaded not guilty at the Central Criminal Court to the murder of Sylvia Shields (60) and Mary Callanan (61) between March 6 and March 7, 1997.
The trial has heard that the two women were living in sheltered accommodation attached to St Brendan's Hospital in Grangegorman at the time.
Counsel for the State Ms Una Ni Raifeartaigh, SC, yesterday called Dr Linda Williams, who told the court that she has been involved in DNA analysis and has worked in the DNA section of Forensic Science Ireland (FSI) since February 2003.
Dr Williams told the court how on September 29 in 2009 she received three self-sealed plastic bags containing thread and buttons belonging to the right cuff of Mark Nash's black pin-striped velvet jacket from Dr Brid McBride, also of the FSI.
Dr Williams told the court that she realised the threads from the black velvet jacket should be kept separate from everything else and she separated the threads from these buttons for DNA extraction.
Describing the procedure she took with the threads in 2009, to the court, Dr Williams explained she extracted DNA from the button threads and they were then compared to the profiles of Sylvia Shields and Mary Callanan.
Dr Williams told the court, the second step she took in the lab was "DNA quantification", to assess the "quantity and quality" of the sample.
Dr Williams then told Miss Ni Raifeartaigh that the third step she took was "DNA amplification".
The court heard how Dr Williams placed the threads into a tray and cut them open with sterile blades and then put the threads from the three buttons into a tube, but not the buttons "to maximise her chance of generating a profile."
Dr Williams told Miss Ni Raifeartaigh she got a profile match from the threads but she couldn't say from "which set of threads it came from."
"The profile taken from the threads matched Sylvia Shields DNA profile," Dr Williams told the court.
Miss Ni Raifeartaigh asked Dr Williams if the profile generated from the threads was a "full or partial profile".
"From the threads, it was a full profile with some minor elements," replied Dr Williams.
The court then heard from Dr Williams how a DNA profile obtained from a "particle" found inside the seam of the right sleeve of the black velvet jacket, also matched the deceased Mary Callanan.
The court previously heard from Mr Brendan Grehan SC, when opening the prosecution's case, how in July 2009, "a spectacular breakthrough" was made in relation to the black velvet jacket with new tests and how DNA belonging to Ms Shields and Ms Callanan, was found on it.
The court also heard that the prosecution have nearly finished giving their evidence.
The trial continues.