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

During the Sharman Inquiry, which investigated the forensic blunder, ESR suggested that the assault victim may have had a brother who had been at the crime scenes and this factor would have greatly increased the chances of gaining a matching profile. When it was revealed that the Christchurch man had no brothers ESR countered with the possibility of an unknown half-brother. The Sharman Inquiry seemed to accept that this was a possibility but the later Eichelbaum-Scott inquiry was less charitable.

Sir Thomas Eichelbaum and Professor John Scott, assisted by an impressive array of legal, forensic and scientific experts, conducted a thorough investigation into the collection, transport, storage, testing and analysis of the samples in question, reporting in November 1999.

Although they never discovered exactly how the mistakes had happened they did determine that the “Rex” and “Pad” samples had been accidentally contaminated with DNA from “Profile N” at an early stage of processing at ESR's Mt Albert laboratories. Extracts from them sent to other laboratories for testing also returned “Profile N”. Numerous recommendations for improving oversight, record keeping and even laboratory ventilation were made.

During the inquiry ESR was asked to check the results of all testing done in July 1998 for any further instances of “Profile N”. Although they initially reported that none were found, later re-tests showed a partial profile consistent with “N” in another sample from “Pad”. They also revealed 25 other “unexplained” profiles in 14 of the 36 samples tested that month.

The David Dougherty case

The independence, neutrality and objectivity of the DNA testing at ESR was seriously challenged when an 11-year-old girl was abducted from her West Auckland home and raped in October 1992. The traumatised young victim described her attacker as clean-shaven but identified her moustached neighbour, David Dougherty, as the offender. Dougherty submitted a DNA sample so that he might be eliminated as a suspect.

The RFLP DNA tests performed at New Zealand's ESR laboratories were unable to gain a result from the semen stains on the girl's underwear and pyjamas. In June 1993 David Dougherty was convicted of abduction and rape and sentenced to seven years and nine months in prison.

In 1993 ESR also introduced DQ-alpha profiling which can return results from very small quantities of DNA but with a limited degree of resolution. Dougherty's defence team requested that the evidence in his case be re-tested using the new technique. The tests were paid for by David Dougherty’s father.

DQ-alpha testing was performed in October 1993 by Dr Peta Stringer of ESR. Stringer identified the DNA of another man in the semen stains but in an act of either professional incompetence or personal malevolence she claimed that faint readings below the threshold of detection recommended by the test kit manufacturers meant that Dougherty could not be excluded as a possible offender even though the DNA did not belong to him or the complainant.

Dougherty’s October 1994 appeal was dismissed as a result of Stringer’s interpretation of the DNA found in the semen stains but it was a molecular biologist, Arie Geursen, who recognised Stringer’s evidence was seriously flawed and consulted with Murray Gibson who had taken over Dougherty’s defence.

Geursen sent samples of the evidence to forensic scientists in Australia and the US who agreed that the faint readings which Stringer said implicated Dougherty were nothing more than artefacts of the testing process. Peta Stringer was now the only expert saying that DNA testing did not eliminate Dougherty as the rapist.

While Dougherty consistently maintained his innocence he served over three years imprisonment in some of New Zealand’s toughest jails before his conviction became the target of Auckland Sunday Star-Times journalist, Donna Chisholm, who questioned the DNA testing procedures at ESR. Chisholm’s investigations revealed the bias of Stringer’s evidence when notes of a 1994 telephone conversation with the Crown Prosecutor indicated that Stringer had an interest in the outcome of the case after she asked “if it will all be enough to get him off?” referring to the unidentified DNA.

Together with forensic scientist Arie Geursen and New Zealand lawyer Murray Gibson, Donna Chisholm began a relentless pursuit for the truth that resulted in a campaign by Auckland Sunday-Star Times to free Dougherty.