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The Christchurch Civic
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The Dominion Post A growing body of wrongful convictions
involving botched dna testing is casting doubt over the "gold
standard" of forensic science in courtrooms, a visiting United States
academic says. While many cases involving dna
evidence were clear cut, a disturbing number were inaccurate, Professor
William Thompson of California University's criminology, law and society
department told a Wellington conference late last week. Professor Thompson, whose
investigations into dna evidence have helped overturn wrongful convictions in
Australia and the US, told Victoria University's Innocence Project that he
"saw errors all the time". He outlined cases in which dna had
been mishandled, cross-contaminated, samples mixed or false matches made.
These were often discovered only after a conviction was re-examined. "There is a strong tendency
for people, even scientists in white coats, to interpret data in the light of
what we expect (to see)." There were also instances of
poorly run forensic laboratories, including the Houston Police Department
Crime Laboratory, which was closed for four years after concerns about flawed
work. Retired High Court judge Sir
Thomas Thorp, who investigated the Peter Ellis Christchurch creche case for
the Government, estimates there could be about 20 people wrongly imprisoned
in New Zealand. About 1 per cent of the prison
population was likely to be innocent, he said. "When you've got
(roughly) 8000 people in prison, 1 per cent is quite a lot." Sir Thomas said many lawyers
lacked the technical expertise to analyse and potentially challenge dna
evidence. He recommended two years ago that
an independent panel, similar to the United Kingdom Criminal Cases Review
Commission, be set up to investigate potential miscarriages of justice. This followed his research into 53
applications to the Justice Ministry claiming miscarriages of justice between
1995 to 2002, of which 26 per cent raised issues that "clearly required
careful investigation", he said at the time. Cases like that of David
Dougherty, whose rape conviction was quashed in 1997 after evidence
established that semen in the victim's underwear was not his, showed New
Zealand was not immune. But Keith Bedford, Institute of
Environmental Science and Research forensics programme manager, said dna
evidence had overturned more wrongful convictions than it had been
responsible for. He said human error was
inevitable, but a double-checking procedure limited this and mistakes were
recorded and acted on. |
