Criminal Law

By Carley Hitchins


Making you a murderer- how unreliable forensic techniques can put you behind bars

Justice Chris Maxwell, President of the Victorian Court of Appeal, made headlines this week when he commented on a number of questionable practises dressed up as reliable forensic evidence.  He noted some forensic techniques, including gunshot analysis, footprint analysis, hair comparison and bite mark comparison, are unreliable. There’s little proof these techniques actually and reliably identify the offender.

With the level of trust placed in forensic techniques in criminal proceedings, there have been a string of wrongful convictions across the world and innocent people locked up on the basis of flawed forensic evidence.

The two critical American reports, published in 2009 and 2016, concluded that DNA analysis is the only forensic technique that is absolutely reliable. Those reports led to major changes to the US and British legal systems. That isn’t the case in Australia.

Justice Maxwell said, “I was asking myself, ‘Why are we not having appeals based on questions of admissibility of forensic evidence?’

“If, as these US reports show, almost none of it is properly validated, then there must be widespread questions of reliability of the science being relied on.”

So how do we navigate this? Justice Maxwell has called on governments around Australia to urgently change the law, so that judges be required to consider the reliability of forensic evidence before it is put before a jury. However, a 2016 High Court ruling has meant that judges cannot stop evidence from being shown to a jury over concerns of reliability.

The real danger with unreliable evidence being put before a jury is that juries are particularly trusting of “experts” who testify that they know that the accused man did it, because his teeth made that bite mark, his fingers left that print, his gun shot the fatal bullet, or he lit the fuel that burned the house.

With the insurgence of society’s obsession with crime stories and TV shows in which intrepid forensic specialists solve crimes again and again through logic and modern technology, it’s easy to see how a jury would place trust in experts in junk science who are seemingly nailing the right people.

But television is not real life, and all too often forensic specialists have come to wrong conclusions based on bad science.

In 1995, David Eastman was convicted by a jury of the murder of Colin Winchester. The circumstantial case against Mr Eastman relied upon forensic evidence that gunshot residue found in his car matched that found at the crime scene.

A 2014 inquiry into the case concluded the forensic evidence “lacked a proper scientific foundation”, and recommended Mr Eastman’s conviction be quashed. By that time, he had served almost two decades in jail following an investigation and trial that were ultimately shown to be severely flawed.

In 1985, Raymond Carroll was convicted after three forensic dentists testified at his trial, all claiming a bite mark found on the leg of a murdered infant matched Mr Carroll’s teeth.

Bite mark evidence has come under scrutiny, with tests showing forensic dentists are often unable to tell if a bite mark was even caused by a human – let alone identify a suspect. Mr Carroll’s conviction was later quashed.

The rigor and precision of forensic sciences is generally accepted by the public, however, it is clear, this is an area for reform – there’s just too much at stake, including the real possibility that an innocent person will be jailed for a crime they didn’t commit.