This week the defence closed its case in the murder trial of Allison Baden-Clay where Mr. Baden-Clay, the accused continued to deny any role in killing his wife and leaving her body at Kholo Creek. The witness list in the Baden-Clay murder trial is long even by the standards of a criminal case with 71 witnesses having been called including friends and family of the Baden-Clay’s, investigators and of course, experts.
As we provide an overview of the expert evidence provided we take note of two particularly interesting points with regard to the use of expert evidence. The first is the number of experts required to provide evidence on the same issues of fact and why that may be the case and the second the increasingly varied use of experts from different fields. This includes information on the mental state of Mrs. Baden-Clay prior to her death to the implications of the presence of algae in the creek where she was found. Second, the number of experts asked to provide evidence on the same issue.
The prosecution over 10 days laid out their theory on the crime, that Mr. Baden-Clay killed his wife. On Day 2 of the trial, the court heard from forensic pathologist Dr Nathan Milne who had conducted the post-mortem examination on Mrs. Baden-Clay’s body. Due to the number of days between her death and when her body was found, Dr Milne found he could not determine an exact cause of death but believed it was not a result of natural causes. He also noted that Allison Baden-Clay had more than the prescribed amount of anti-depressants in her blood but suggested that could have been affected by decomposition. His findings were supplemented by evidence from a Dr Nicholas Burke, Dr Lawrence Lumsden and counselor Carmel Ritchie who discussed problems within the Baden-Clay marriage and the effect it had on Mrs. Baden-Clay.
Dr Nicholas Burke, a GP who had treated Mrs. Baden-Clay said she had not shown any signs of being suicidal. On Day 7 of the trial Dr Tom George, who treated Mrs. Baden-Clay periodically over 9 years, navigated the difficulty of providing evidence on a former client expressed that though it is not uncommon for suicide to be a surprise even to professionals, he had never found her to be suicidal. Professor Olaf Drummer from the Victorian Institute of Forensic Medicine further told the court the levels of Zoloft in Mrs. Baden-Clay’s liver were not in his opinion consistent with an overdose. The number of experts relied upon in forming an opinion on Mrs. Baden-Clay’s mental state and usage of prescription medicine likely reflect the high standard of proof the prosecution must meet.
A potentially damning statement was made on Day 6 of the trial by forensic physician Dr Margaret Stark, who examined photos of scratches on Mr. Baden-Clay’s face and found them “typical of fingernail scratches”. Two forensic medical experts, Dr Robert Hoskins and Dr Leslie Griffiths as well as forensic physician Professor David Wells supported this supposition. One interesting aspect of the cross examination of Professor Wells was the admission in cross-examination that an in person examination of injuries was preferable over photos as performed by Professor Wells. This reflects discussions raised over the reliability and ethics of using external experts to make conclusions without personal experience in the case
The prosecution then turned to Dr John Jacob, a microscopic algae expert who found no evidence that Mrs. Baden-Clay had drowned in Kholo Creek. This proposition was made on the basis of two species of algae present in the water that were not found in samples of the deceased’s bone marrow or liver. His evidence demonstrates the broadening nature of expert evidence and how increasingly, the search for appropriate experts extends to fields previously never considered. Similarly, a Dr Gordon Guymer, the director of the Queensland Herbarium, was called to the witness box to identify six different species of plant on Mrs. Baden-Clay’s body and hydrologist Martin Giles was called to examine the level of water and flow in Kholo Creek. Forensic entomologist Professor Wallman also gave evidence by phone on his examination of insect specimens at the crime scene and the implications they had for the time of Mrs. Baden-Clay’s death. The prosecution then closed its case.
After allowing Mr Baden-Clay to speak in his own defence, the defence called on expert witness Dr. Robertson, a forensic toxicologist, who has been a toxicologist for 20 years and for the majority of that time specialised in forensics. He reviewed the results of the post-mortem examination on Mrs. Baden-Clay and commented on the adverse effects of the anti-depressant drug Zoloft which contains Serotonin. Dr. Robertson noted that Serotonin could increase suicide ideation and with elevated levels could lead to confusion, increased agitation and unusual behaviour. However, he admitted there could be varying reasons for the elevated levels of Zoloft in Mrs. Baden-Clay’s body and it did not necessarily cause her death.
His testimony was supplemented by psychiatrist Dr. Mark Schramm who reviewed Mrs. Baden-Clay’s medical records. He commented that more than half of those who commit suicide do not leave a note and often it is a surprise or impossible to predict. While he thought that Mrs. Baden-Clay would be a person at risk of suicide, maternal instincts and plans made for the future are preventative factors. His report was reviewed by Professor Diego De Leo, a suicidologist from Griffith University in Queensland.
That was all the expert evidence relied upon by the defence. The higher number of experts called upon by the prosecution is a consequence of the burden of proof resting upon them. Instead what the defence were required to was to present merely an alternative theory on the case, being that Mrs. Baden-Clay may have as a result of suicide taken her own life. The jury has continued to deliberate into the current week. One question from the jury to the Judge as to what the implications of an alleged lie suggests that the evidence provided by experts has at least convinced the jury that Mr. Baden-Clay did not injure his face by shaving. Whether this means they are convinced beyond reasonable doubt of his guilt remains to be seen.
What is already evident is the important role experts have in providing some guidance in the determination of guilt and hopefully justice. As different fields continue to be relied upon in filling in the blanks for the court it is likely services such as Experts Direct will be needed to connect appropriate and experienced experts with legal teams.
This article was prepared in conjunction with Susan Flynn.