Criminal Law and Forensic Evidence

Forensic Science in Criminal Trials: Is It a Double-Edged Sword?

Forensic evidence has long been used as a weapon in criminal trials. From fingerprints to handwriting and DNA, scientific analysis is a powerful force, used to exonerate the innocent and convict the guilty. It is also now used to hunt down killers, whose crimes were committed in the decades before science developed DNA profiling, and crack cold cases.

However, the well-documented role of science in wrongful convictions, both in Australia and around the world, is alarming. Unvalidated or improper forensic science has been a factor in nearly half of wrongful convictions in the US, according to the US Innocence Project. In Australia, researchers suggest that proportion is 31%.

How does this happen? And what can we do about it?

In a recent Australian Bar Review article, biometric DNA experts Smith and Urbas examine how forensic science has contributed to Australian criminal appeals over the past 100 years.

They discuss six famous cases of miscarriages of justice and highlight the ongoing issues associated with the use of scientific evidence, including DNA, in criminal trials. The authors subsequently argue the need for reforms to improve scientific standards within the criminal justice system and evaluate an approach implemented in the United Kingdom.

Wrongful convictions and miscarriages of justice – when forensic science fails

A miscarriage of justice occurs when an innocent person is found guilty of an offence, and is wrongfully convicted and, in serious cases, wrongfully imprisoned.

The undesirability of a miscarriage of justice and wrongful conviction – for not only the person concerned but society generally – is perhaps best encapsulated by Blackstone’s ratio from the 1760s:

“It is better that ten guilty persons escape than that one innocent suffer.”

Unfortunately, though, there are many Australian cases where forensic science has played a substantial role in convicting the innocent.

Examples of wrongful conviction and miscarriage of justice in Australia


Year of crimeDefendantStateCrimeSentence Time served Legally exonerated
1922 Colin Ross Victoria Murder Execution Hanging Yes, posthumously
1964 Alexander McLeod-Lindsay NSW Attempted murder 18 years 9 years Yes
1977 Edward Splatt South Australian Murder and sexual assault Life imprisonment 7 years No
1980 Lindy Chamberlain Northern Territory Murder Life imprisonment 3 years Yes
1999 Frank Button Queensland Rape 6 years 10 months Yes
2006 Farah Jama Victoria Rape 6 years 16 months Yes

Forensic science: is this the best we can do?

These cases highlight the need for science, when used in criminal trials, to be verifiable and applied consistently. They also highlight the different avenues innocent people must travel to finally get justice.

The Hon Michael Kirby AC CMG points out that some observers will say that the Australian judicial system got it right in the end: “No system of criminal justice is perfect. Ours is better than most. Ours remains committed to avoiding miscarriages of justice. Some failings are inevitable in any human system.”

Despite there being some element of truth in these statements, the former High Court judge urges a “commitment to excellence, first-class science, accuracy and transparency as we progress along the path of involving increasing forensic evidence (especially DNA evidence).”

Committing to excellence: an opportunity for reform

Our mechanisms for correcting wrongful convictions have traditionally been approached on an ad hoc basis, and often only after public agitation in relation to specific cases. Legislative changes allowing secondary appeals and exceptions to the double jeopardy rule in certain circumstances, for example, are an attempt to keep up with leaps in science.

Historically, the correction of wrongful convictions fell within the responsibility of the executive, and pardons sometimes followed royal commissions. In more recent times, innocence projects are an attempt to recalibrate the scales of justice. This model was used in developing an administrative body to review examine claimed miscarriages of justice in New South Wales.

In 2003, the Australian Law Reform Commission recommended that a Commonwealth body be established to hear post-conviction review applications on the basis of DNA evidence from throughout Australia. This recommendation has never been adopted.

Commentators also argued that a body should be established in Australia similar to the Criminal Cases Review Commission (‘CCRC’) in the UK. The CCRC is an independent body that conducts transparent and impartial investigations into suspected miscarriages of justice. It can refer claims of wrongful conviction to the Court of Appeal where it considers there is a ‘real possibility’ the conviction could be overturned on the basis of evidence or arguments not presented at trial, or other exceptional circumstances.

Along with a consistent national approach to reviewing convictions and acquittals, improvements to the evaluation of forensic science during criminal trials is also needed. The validation of scientific techniques, improved standards and protocols in collecting samples and analysing data, acknowledging the risk of inaccuracy with all forensic science is required.

The road ahead isn’t clear, however steps must be taken to ensure confidence in the rule of law as science continues to evolve rapidly – so that the miscarriages of justice we read in the cases above aren’t repeated time and time again.

Read the complete article A Century of Science in Australian Criminal Trials inside the Australian Bar Review on Lexis Advance.

The Australian Bar Review is produced under the auspices of the Australian Bar Association and provides a forum for the scholarly discussion of current issues in legal doctrine and procedure throughout Australia.

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