Senior police officers in the North have tried for years to interfere with the workings of the north's independent Forensic Science Agency, Belfast Crown Court heard today.
The disclosure came from a senior scentific officer who also revealed that the Agency was starved of both cash and staff.
Mrs Ann Irwin, with 22 years experience, told Lord Justice Nicholson that in the last seven years since becoming a firearms' residue expert, such police demands made of her and the Agency to "compromise" their scentific work were all refused.
Mrs Irwin revealed the demands were made after police had failed to follow proper procedures and tried to "retrieve" the situation by requesting that tests for firearms' residue on clothing and other materials taken from suspects and crime scenes bemade despite the possibility of contamination.
The senior scentific officer, giving evidence at the trial of 34-year-old Thomas Noel Abernethy, said she refused to carry out such impossible tests because she wasn't prepared to issue results she was not prepared to stand over.
Tests on clothing taken from Abernethy from Glebe Mews Dungannon, who denies attempting to murder two policemen and a woman voter in a gun attack on St Mary's Primary School polling station on general election day Jnue 7 2001, could not be carried outbecause police had "incorrectly packaged" them.
Mrs Irwin's disclosure came as she was being questioned by defence QC Philip Magee on the notes she made concerning Abernethy's case.
She had noted that despite tests results being "required urgently", Abernethy's clothing and that of a second man arrested with him were not delivered to her laboratory until the following day and that: "clothing of Abernethy was incorrectly packaged asneither Gough or D Matland had nylon bags".
Her notes also revealed that police, who thought the Agency was fully staffed 24 hours a day seven days a week. were puting in requests "piece-meal, and as a result some evidence was lost".
Mrs Irwin later noted that: "they (the police) tried to retrieve the situation by asking the lab to compromise its science".
Asked by Mr Magee did a senior officer in the PSNI ask her and the Forensic Agency to "compromise its science" in Abernethy's case, Mrs Irwin replied she was being asked to carryout an examination whose results she could not stand over.
"And you refused to do it?" asked Mr Magee.
"I could not stand over any results that resulted", (from such tests), said Mrs Irwin.
Lord Justice Nicholson then asked of the scientist: "Was this the first occasion you were asked to compromise?".
"No, it would not be the first occasion," she replied.
Asked by the trial judge in what type of cases and on how many occasions did the police make such requests, Mrs Irwin said that such requests were made: "in similar circumstances were clothing had been incorrectly packaged for CDR", and that they hadbeen made "over the past seven years".