Drug tests for courts a waste of time says forensic scientist

Labs spend hours on preliminary testing which is pointless as defendants later plead guilty

Drug tests required by the courts are wasting significant resources in the Forensic Laboratory because defendants later plead guilty, a senior scientist has warned.

So-called presumptive tests "basically" confirm a substance is a controlled drug, according to Dr Tom Hannigan, the director of chemical sciences at Forensic Science Ireland.

Fewer such preliminary tests could leave more resources “available so that we can focus . . . on more serious cases”, said Dr Hannigan, who will address up to 260 of the State’s prosecuting lawyers at a conference in Dublin Castle.

Dr Hannigan highlighted presumptive drug-testing rules which lead to forensic scientists spending significant hours on tests that are later not needed because the defendant pleads guilty.


Personal possession

“The system was intended to deal with section 3 [drug] cases, personal possession cases, where people are pleading guilty. Most of these cases, 95 per cent of these cases, end up with guilty pleas,” he said.

“It’s not really working as well as we would wish . . . Typically what happens is defence solicitors will demand a certificate of analysis from the laboratory as a means of getting an adjournment.

“The certificate has to be produced and then when they’ve got the certificate, they plead guilty – which defeats the whole purpose of the scheme.

“If you’re admitting to the possession of a controlled drug, what’s the certificate of analysis needed for? Unfortunately, there are District Court judges that allow this to happen.”


Microscopic DNA traces so beloved of TV detectives series, such as


, can solve many crimes – but not every one, according to Dr Hannigan.

“DNA is a tremendous technique but it can’t do everything and . . . traditional scientific techniques, other evidence types, also have a role to play,” he argues. “There’s more to forensic science than DNA and you – prosecutors – need to be aware of this .”

Forensic evidence – tiny traces of lead, antimony, and barium in gunshot residue, matching fibres from clothes or furniture, and footprints or tyre-tracks – are still crucial tools in the fight against crime.

Some of the evidence is so minute, such as fibres, paint and glass particles collected by sticky pads, it later has to be magnified 200,000 times under an electronic microscope.

Peter Murtagh

Peter Murtagh

Peter Murtagh is a contributor to The Irish Times