Australia had an instance of a false conviction that was due to a DNA database match fairly recently. It is the case of Farah Jama, who was convicted of rape in a trial in Melbourne, Victoria in 2008 and served a year in prison, before being cleared in late 2009.
The case involved a woman who was found unconscious in a nightlcub toilet. She was taken to a rape crisis centre in a Melbourne hospital and was given a rape kit. The vaginal swab contained a single sperm and some fragments, yielding a male DNA profile. Although the woman could not remember what had happened, this finding was taken to be a confirmation of rape, as she had not had sex in some time, A few months later, the profile was matched to a sample that had been taken from Farah Jama a few months earlier when he was the subject of a different rape allegation. That allegation had already been withdrawn by then; however, in Victoria, such a profile can nevertheless remain on the database for a year after the sample was first taken.
At his trial, Jama denied all the charges and his entire family provided an alibi. However, the jury convicted him on the basis of the DNA match (and, perhaps, his possibly false denial of ever having been in any nightclub.) But, prior to his appeal, the prosecution realised another link between Jama and the nightlclub incident. The link was that both the complainant in the withdrawn allegation (who had Jama’s semen in her hair) and the woman in the nightlclub incident had attended the same rape crisis centre one day apart. This raised the possibility that Jama’s DNA was transferred from the first complainant to the swab from the second one. Everyone now accepts that this is almost certainly what happened, as there was no other evidence linking Jama to the rape, and the prosecution theory of the rape was actually so unlikely (the nightlclub was an ‘over 30s’ event packed with Caucasians, while Jama is a Sudanese-origin teenager), and the rape crisis centre lacked adequate anti-contamination processes, . Indeed, there was almost certainly no rape at all. Jama was acquitted on appeal and given $1M ex gratia compensation.
Obviously, the immediate blame for the false conviction (and false perception that the woman had been raped) is contamination. However, the conviction could never have occurred without a DNA database, as Jama was never even remotely a suspect for the nightclub incident. Disturbingly, although the error was discovered within a year and prior to Jama’s first appeal, the discovery of the error appears to be serendipitous (based on the coincidence that the same doctor attended both women.) It is easy to imagine scenarios where the error wouldn’t ever have been discovered. Although Victoria has acquired a reputation for being prone to contamination (with at least two other cases of lab contamination in the past decade, one leading to an arrest), it is otherwise a strong jurisdiction in terms of trial processes, with reasonably independent prosecutors and judges, and relatively well resourced defence lawyers and courts.
An official report on the error is available here: http://www.justice.vic.gov.au/resources/4716aa25-9e73-477a-9a14-4e407b4b94ed/vincentreportfinal6may2010.pdf. I have a slightly different take in a chapter of a recently published book (Hunter & Roberts, Criminal Evidence and Human Rights, Hart, 2012.) For a short summary, see the following online article: http://inside.org.au/genetic-injustices/.
Jeremy Gans, Forensic Science, Statistics and the Law