THE INFLUENCE of television programmes can lead to an unnecessary emphasis on forensic evidence, according to a leading forensic scientist.
Maureen Smyth, head of the DNA section of the Forensic Science Laboratory, was speaking at the annual prosecutors' conference at the weekend.
She said that the prevalence of television programmes featuring forensic scientists had led juries to expect forensic evidence or DNA profiling.
"Is the satisfaction of juries' expectations the best use of public resources if there is ample other evidence and the DNA or forensic evidence is inconclusive or neutral?" she asked.
The Forensic Science Laboratory selected the cases it worked on on the basis of what was in the file and what supplementary information was available. There were always some cases to be dealt with urgently and others to be dealt with eventually, and some that should not have come in at all.
Referring to the recent Omagh bombing trial, where the judge had been very critical of the police and the forensic evidence, Dr Smyth said this was essentially a cold case review, where modern techniques were applied to items stored years ago.
The judgment was very critical of how the samples were taken and stored, and of how the police described this.
The technology used for dealing with "low copy number" (LCN) samples had been developed in England. There were problems with this technology, as it could detect more than one source for the DNA and could be variable on re-tests.
"Every time the scientist goes to the sample, he or she can get a different result," she said.
A better solution was to improve the extraction of DNA and ensure there were better samples, she said.
Tom O'Malley BL told the conference that there was pressure for prosecutors to make submission on sentencing at a trial, especially as the DPP could appeal against undue leniency. This suggested the prosecuting counsel should indicate at the original trial what the framework should be for an appropriate sentence, he said.
However, this should be preceded by an exercise that would establish the key indices for gravity in most offences.
Such an exercise was necessary anyway in order to generate a rational and consistent sentencing system, and the courts themselves needed to have such information in order to develop a consistency of approach towards sentencing.
The furthest prosecutors should go would be to make submissions on a scale of gravity, he said.
The selection of sentence was exclusively a judicial task and the prosecution should rigorously avoid any recommendation as to sentence.