The John Tonge Centre, DNA evidence and miscarriages of justice - Part 4

Gibson successfully petitioned the New Zealand Governor-General in June 1996 and Dougherty was granted an appeal against his conviction. Two months later the New Zealand Court of Criminal Appeal quashed Dougherty's conviction and ordered a re-trial stating that the interpretation of the ESR results by three independent scientists was materially different from Stringer’s interpretation. Dougherty was finally released from prison after three years and nine months pending re-trial.

In April 1997 a New Zealand High Court jury acquitted Dougherty on all charges but he was yet to clear his name in the eyes of the public. In November 1997 New Zealand Justice Minister, Doug Graham, told the New Zealand media that Dougherty had not proved his innocence “on the balance of probabilities”.

Three years later, following a further series of tests with the most sophisticated equipment available - all of which failed to detect the slightest trace of his DNA in the stains, Dougherty was finally found to have proved his innocence and was compensated almost NZ$900,000 for wrongful imprisonment.

Chisholm and the Auckland Sunday Star-Times were vindicated in their pursuit of justice for an innocent man and the newspaper editorialised:

The David Dougherty case raises serious questions about New Zealand's justice system. An innocent man spent more than three years in jail. He was finally released, not by the efforts of those who run the system, but as the result of a campaign by a scientist, a lawyer and a journalist. The campaign revealed serious errors of judgment by a state forensic scientist. It also exposed a worrying official culture which appears to favour the prosecution rather than the defence.

In response to an allegation by New Zealand prosecutor Mark Woolford that Donna Chisholm and the Sunday Star-Times were guilty of irresponsible reporting the newspaper responded:

Prosecutor Mark Woolford has accused the Sunday Star-Times of irresponsible reporting. Journalist Donna Chisholm, he claims, has acted as a campaigner, not as a journalist. Woolford is hopelessly muddled. This newspaper reported the flaws in the prosecution case and the prosecution, naturally enough, did not like it. It revealed the shortcomings in Stringer's evidence and the misguided attitudes of the ESR and neither Stringer nor the ESR liked that either. Exposing injustice and campaigning for the truth are not irresponsible acts, Mr Woolford: they are the greatest glories of the free press. We are immensely proud of our role in the campaign for justice for David Dougherty.

Finally, in September 2002, another arrest was made over the attack that had caused David Dougherty’s wrongful imprisonment. He is now universally recognised as an innocent man while the forensic scientist whose unprofessional conduct condemned him to over three years of imprisonment and a decade of public vilification migrated to Australia.

Dr Peta Stringer was employed at the Victorian Forensic Science Centre where she is credited with developing the “CrimTrac” DNA database policy whereby a “hit” is declared if 16 or more pairs of the 18 genetic markers in two samples match, although it takes 18 out of 18 markers to make a true match and any less is either a lab error or an exclusion. When a match policy like that advocated by Stringer is used on a large DNA database it could generate an exaggerated rate of “cold hits” that carries a significant risk of wrongful convictions. But as Dr Stringer told a Victorian parliamentary inquiry into DNA databases: “There are a number of ways that you can count matches”.

The independence of DNA testing facilities and the integrity of the personnel using them must be of the highest standard if DNA evidence is to continue being accepted as quality evidence in courts of law. That quality of evidence falls into disrepute when scientific objectivity and neutrality is replaced with a culture of forensic elitism that is significantly tailored to the prosecutorial pursuit of suspects through the judicial system.