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Expert Activism: How expert evidence derailed a conviction

AiPol Journal
September 2023

Loquitur was pleased to have drafted an article for the Australasian Institute of Policing (AiPol) Journal in their Q3 2023 special edition on Expert Witnesses and their Critical Role in Prosecution and Litigation.  The article focusses on the case of Wood v R in which a police expert witness in a high profile murder trial became too closely involved in the investigation, and how his account of his involvement in a published book lead to an appeal of the conviction.  The case is a good example of the need for expert witnesses to remain impartial, and the effects of when they fail to do this. 

Medico-legal expert witness - doctor with stethoscope. Expert Opinion


Wood v R was a criminal case regarding the death of Ms Carolyne Byrne who died of an apparent suicide by jumping off a cliff onto rocks at the Gap at Watsons Bay in Sydney. Gordon Wood was the driver for controversial businessman Rene Rivkin and was Ms Byrne’s boyfriend at the time. Mr Wood was subsequently charged with Ms Byrne’s murder.

This case contains several important points and lessons for police officers, investigators, prosecutors, legal teams and expert witnesses, and in some respects is a lesson in what to avoid when engaging expert witnesses to help in police investigations and prosecution.


One issue at the trial was whether Ms Byrne had jumped or was thrown from the rocks. Expert witness evidence was called in respect of this. One expert witness for the prosecution was Associate Professor C, an engineer with an expertise in physics. Mr Wood was convicted.

The conviction was appealed. One (of several) grounds of appeal was the expert evidence of A/Prof C. After the conclusion of the trial, but prior to the hearing of the appeal, A/Prof C published a book titled “Evidence for Murder: How Physics Convicted a Killer”, and other information about his engagement as expert witness on his website. This was a comprehensive account of A/Prof C’s opinion of various aspects of the evidence and of his involvement in the investigation. The book acknowledged contemporary concerns about the integrity of expert evidence, but nonetheless revealed serious problems about his own involvement in the police investigations. These publications showed the energy he applied to assisting the police, no doubt a result of worthy intentions.

At the appeal the published material and other involvement of A/Prof C’s was considered fresh evidence and considered accordingly.


Book Publication

The court considered the duties of expert witnesses generally, and the role of A/ Prof C in particular. The Judge found that if the published material had been available at trial it would have significantly diminished A/Prof C’s credibility as a witness. The information in the book :

  • Made plain that A/Prof C approached his task as expert with the preconception that Mr Wood had killed her.
  • Suggested A/Prof C saw his task as being to marshal the evidence which may assist the prosecution to eliminate the possibility of suicide and leave only the possibility of murder.
  • Was “replete with recitations of his role in solving the problem presented by the lack of physical evidence and records how he was able to gather the evidence which enabledthe prosecutor to bring proceedings against the applicant”.

There were also various fundamental issues with the assumptions made by A/ Prof C and the tests he conducted.


Role of A/Prof C as Part of the Investigation Team

It was clear from the book, and other evidence adduced on the issue, that A/ Prof C was involved in the investigation of the matter to an extraordinary degree. He shared the suspicions of police and coroner. He worked closely with the police and promoted his own case to police. In this way, the “independent” expert was an active part of the police investigation team who worked closely with the police to prove the police hypothesis.

Additionally, A/Prof C worked with the police to support one (lay) witness’ version of event and to “convince” the prosecutor to bring the prosecution. There was even a suggestion that A/Prof C had tried to influence police evidence as to the death of Ms Wood. This created serious doubts as to the apparent impartiality and independence of A/Prof C in his role as an expert witness.

The court found that once an expert has been engaged to assist in a case, there is a significant risk that he or she becomes part of “the team” which has the single objective of solving the problem or problems facing the party who engaged them to “win” the adversarial contest.

Additionally, several other factors arose as a result of this particularly close relationship between A/Prof C as “expert” and the investigation team. At one point during the investigation, A/Prof C was asked by police to provide an expert report on forensics. A/Prof C gave the report despite having no experience in forensics, rather being an expert in physics.

Further, documents, including emails between A/Prof C and the police, were not produced until the evening of the 35th day of the trial. This caused disruption to the trial, necessitating its postponement and thus fracturing the cross-examination of the witnesses. The emails also disclosed information for the first time in relation to witnesses who had already given evidence and had been excused from the trial.



It considered whether an expert’s evidence is inadmissible if the expert has breached the Expert Witness Code of Conduct. It found that while this does not necessarily make the evidence inadmissible, it may do so if the breach is sufficiently grave.

Here, A/Prof C had clearly breached the Expert Witness Code of Conduct, and to such an extent that his evidence was inadmissible. The book published by A/ Prof C, and his close relationship with, and influence in, the investigation and prosecution had the consequence that his opinion on any controversial matter should have minimal, if any, weight . A/Prof C “took upon himself the role of investigator and became an active participant in attempting to prove that the applicant had committed murder. Rather than remaining impartial to the outcome and offering his independent expertise to assist the Court he formed the view… that [Mr Wood] was guilty and it was his task to assist in proving his guilt.

If the subsequently published information had been “available to the defence and the extent of A/Prof C’ partiality made apparent, his evidence would have been assessed by the jury to be of little if any evidentiary value on any controversial issue.”

The conviction was quashed, and Mr Wood was acquitted.


Comment and Lessons Learnt

Police officers, investigators, prosecutors, legal teams and expert witnesses can learn a lot from this case.

At the outset we note the interesting point that a failure to comply with the Code of Conduct will not automatically mean the expert witness’ evidence is struck out (although it may do if sufficiently serious). However, it will certainly be a factor in the consideration of the weight of evidence and credibility of the expert witness. This is practical consideration by the Courts, and it will be a question of degree as to what the effect of such a failure is.

We are reminded of the expert witness’ need for impartiality. Experts must be impartial, and be seen to be impartial. This is particularly important in more recent times when an expert’s online media profiles will often be readily and publicly available for others to read. While obviously this includes their professional profiles (LinkedIn, Twitter etc.) It may also include any personal profiles (Instagram, Facebook etc.). It is common for police investigators and legal teams to research and investigate the activities of all opposing witnesses on these forums, and indeed they should also investigate their own witnesses as well to prevent any such issues arising. Any suggestion of an agenda or activism will invite challenges to the witness’ evidence, difficult procedural steps, and can lead to very awkward cross-examination and attacks on credibility.

It also serves as a reminder of the need to comply with relevant codes of conduct and a lesson that an expert’s primary duty is to the Court, rather than a party instructing them. Nor are witnesses engaged for their own personal aggrandisement. Experts who assist in a police investigation must take special care to preserve their independence, as indeed must the police investigation team who engage them. If there is any suggestion that the independence of the expert has been or could be compromised from their involvement in the investigation their position as a witness should be re-considered.

That is not to say there is no benefit in having a subject matter expert assist in a police investigation. There clearly is, and indeed it can be, essential. However, in circumstances such as this a second expert should later be engaged: with the second expert to provide the expert witness evidence to the Court. The distinct roles of those experts should be respectfully observed, and these experts should be treated differently so as to avoid the “contamination” of the expert witness’ evidence.

We also see from this case the dangers of a very close relationship between expert witness and police investigators. The expert should in fact be an expert in the relevant subject matter, a point which the police should independently check. There will also be issues of disclosure between police and expert which may arise, and if these do arise they should be addressed promptly with the issue identified and the action taken to address it, officially recorded.

Finally, we see the catastrophic effect of a failure to comply with these principles. It will reflect poorly not only on the evidence of that expert, but also on the credibility of other police witnesses, and indeed potentially the entire investigation and prosecution. It may severely disrupt or prejudice the trial process itself. This may also have significant cost consequences, as well as reputational damage on the expert and the relevant investigators, prosecutors and their respective organisations.


About the author: 

Tom Nevin is a solicitor and director at Loquitur, Australia’s leading witness training provider.  Specially prepared courses are available for lay (factual) witnesses, expert witnesses and other sorts of professional witnesses, such as medical professionals, police witnesses, emergency responders and public servants.


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