DNA evidence on sleeve ‘discounted’ by witness

A forensic scientist has told a murder trial he has discounted the fact that DNA profiles from two women killed nearly 20 years ago were found on the sleeve of a jacket belonging to the murder accused.

DNA evidence on sleeve ‘discounted’ by witness

Mark Nash has pleaded not guilty at the Central Criminal Court to the murder of Sylvia Shields and Mary Callanan between March 6-7, 1997.

The court had previously heard that a profile taken from the button threads of the right sleeve of the black velvet jacket matched Ms Shields’ DNA profile and a DNA profile obtained from a “particle” found inside the seam of the right sleeve of the jacket also matched Ms Callanan.

Reading Philip Avenell’s conclusion, Brendan Grehan, prosecuting, said: “Considering all of the information, it remains my view, there is a real possibility that the scientific findings may have arisen because of contamination in the scientific lab.”

To which Mr Grehan replied: “I’m suggesting the most likely explanation is that, to have both DNAs belonging to both victims on the sleeve, is because he was there at the scene.

“You haven’t supported your opinion with any proper scientific basis which can be evaluated and furthermore it is of great significance that the DNA recovered was on the bottom of the right sleeve.”

“I don’t accept the significance aspect,” replied Dr Avenell.

“Do you not attach any significance that two DNA profiles that matched the women were found on the sleeve of the jacket?” asked Mr Grehan. “No, I don’t attach significance to that,” replied Dr Avenell.

Mr Justice Carroll Moran told the jury this was the end of the evidence and he would resume the case on April 14, with it finishing the week of April 20.

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