By Andrew L. Urban
Tunnel vision by police investigators is one of the leading causes of wrongful convictions, according to a respected former Detective Inspector, when alternative theories to the crime are not considered and potential suspects are eliminated from the investigation. ‘Improper forensic science’ is another.
Over the past 12 months, I have written extensively on the case of Sue Neill Fraser, arguing that flaws in the police investigation and errors at her trial (forensic and otherwise) have contributed to a catastrophic failure of justice. The investigation was a perfect example of tunnel vision – and the jury was given no evidence to support the prosecutor’s speculation about the act of murder.
(Neill Fraser is serving 23 years in Risdon prison for the 2009 murder of her partner Bob Chappell, who disappeared off their yacht, Four Winds, in Sandy Bay, Hobart, and whose body has never been found, nor was a murder weapon produced in evidence.)
In the process, there has been extensive correspondence and comment in the media, notably in the pages of the Tasmanian Times, in which several people argue (inter alia) that the system doesn’t get it wrong, the jury verdict is safe and that Neill Fraser is guilty.
The main point that is overlooked by such commentators is that in a circumstantial case where there is no body, no weapon (except one fancifully conjured up by the prosecution) and no forensic evidence to link the accused to the crime, the law stipulates the conditions that must be met for a safe conviction, namely that no other explanation is possible but that the accused committed the crime.
That’s because there is great risk of the justice system getting it wrong as history has shown. I have added my voice to those who wish to see a full review of the case, by a mainland judge; a review to satisfy the need for confidence in the justice system, especially as her two appeals that have failed have been severely criticised by legal experts.
Errors by investigators, as well as prosecutors and yes, even judges, are made all over the world; the most recent example is a report from Washington, about hundreds of serious convictions in doubt across the US, after the discovery of systemic errors in FBI forensic reporting over several years.
Those concerned with the case of Neill Fraser will find striking echoes for their alarm at her conviction in the article in the July 2014 edition of The Police Chief magazine (US), by Dr Kim Rossmo, a former Detective Inspector with the Vancouver Police Department, now at the Criminal Justice Department of Texas State University. The following is an edited extract from the article.
“It seems most unlikely that, with all the checks and balances of the criminal justice system, someone today could be convicted of a crime he or she did not commit. The unfortunate reality, however, is that it does happen.
Tunnel vision—one of the leading causes of wrongful convictions—results from a narrow focus on a limited range of possibilities. Consequently, alternative theories to the crime are not considered and potential suspects are eliminated from the investigation. This heuristic is particularly ill-suited to solving complex, dynamic investigations. Focusing on the first likely suspect, then closing the investigation off to alternative theories (1) is a recipe for disaster.
Confirmation bias is a form of selective thinking in which an individual is more likely to notice or search for evidence that confirms his or her theory, while ignoring or refusing to search for contradicting evidence (2). Confirming evidence is given more weight, while contradicting evidence (3) is given less weight. The components of confirmation bias include failure to seek evidence that would disprove the theory, not utilizing such evidence if found, refusing to consider alternative hypotheses, and not evaluating evidence diagnosticity.
Investigations should be led by the evidence, not by the suspects. Case conclusions should be deferred until sufficient information has been gathered, and tunnel vision should be avoided at all costs. Investigative managers must remain neutral and encourage open inquiries, discussion, and dissent. Assumptions, inference chains, and uncertainties need to be recognized and recorded. Outside help should be sought when necessary.”
Relevance to Neill Fraser case:
(1) Given that Bob Chappell disappeared and his body has never been found, alternative theories may include :
a) accidental drowning,
b) kidnapping by persons unknown via the grey dinghy sighted alongside Four Winds by several witnesses the afternoon of his disappearance,
d) murder by a stranger or strangers gaining access to the yacht. (He was alone at the time.)
(2) Police ignored reports of a grey dinghy reported by witnesses, who saw it alongside Four Winds that afternoon.
(3) A sample of DNA found on the yacht was later matched with then homeless 16 year old Meaghan Vass. Police accepted the possibility that her DNA was ‘transferred’ onto the boat via a policeman’s shoe; Vass was unwilling to be questioned again and neither the police nor the court pursued her. A July 2014 forensics report from Victorian Police Forensics lab confirms the DNA sample was consistent with direct deposit, not transfer.