Expert evidence in criminal trials
On Friday 23rd November 2018 our Principal Lawyer, Mr Michael Moussa successfully sought approval from the Police Crimes Manager to withdraw a very serious allegation of a domestic violence.
The allegation, in short, was that our client was alleged to have hit his wife with a closed fist occasioning actual bodily to harm to her.
The allegation was that one night while they had an argument, the pair entered into a heated discussion. In frustration, it was alleged that our client punched her with a closed fist to her face causing intense bruising to her left side. Our client vehemently denied laying a finger on her.
As a result of the injury, the alleged complainant went to hospital to be treated. She disclosed to the Doctors treating her two inconsistent versions. Initially she told the Doctors she was hit by a door. But when probed more by the Doctor, she said:
“It was my husband. We had a fight and he punched me on the left side of the face”.
The Doctor recorded the two statement in their internal file management system.
As a result of the disclosure, the doctor contacted police who attended the hospital shortly after and ask the complainant for a statement.
The police subpoenaed the medical file and wished to rely on the Doctors’ notation to prove their case.
An expert certificate was served on Mr Moussa and alarmingly Doctor made the following statement of opinion:
Based wholly or substantially on the above knowledge, I am of the opinion that:
Ms X’s injures are consistent with the allegation of being struck by her husband to the left side of her face (our emphasis) (the Opinion).
EXPERT EVIDENCE IN CRIMINAL TRIALS
In criminal trials or hearings witnesses are generally prohibited from expressing opinions on matters that are to be determined by the jury or fact finder. Opinions offered by witnesses are excluded because they are not experts or do not have specialised knowledge. However expert witnesses may be called as witnesses if they (1) possess ‘specialised or expert knowledge’ and (2) provided their opinion ‘wholly or substantially based’ on that specialised knowledge. This is consistent with the provisions of Section 79 Evidence Act 1995 (NSW).
The question of who and how the jury or fact finder should rely on expert testimony is fraught with problems. For example, what happens when an expert testifies outside of their specialised expertise or in a way that is just simply an everyday ordinary opinion?
Mr Moussa reviewed the expert certificate meticulously and wrote to the police indicating the expert report does not otherwise satisfy the exception of opinions based on specialised knowledge, because the opinions of the Doctor were not wholly or substantially based on a specialised knowledge.
Rather, Mr Moussa argued that the Doctors opinion was based on his comparison of the inconsistent statements made by the alleged complainant. Mr Moussa argued that:
“There is no doubt that an opinion based on the comparison of inconsistent statements is outside any specialised knowledge which Doctor X may have”.
THE CASE LAW
The High Court in the case of Honeysett v The Queen  HCA 29 had the opportunity to clarify such problems in respect of what happens when an expert testifies outside of their specialised expertise or in a way that is just simply an everyday ordinary opinion.
THE FACTS OF HONEYSETT
In Honeysett, the accused had been convicted of an armed robbery carried out at a local suburban hotel. The event was recorded by CCTV cameras, which had shown one of the robbers holding a distinctive pink-handled hammer. That person’s head was covered in a pillowcase or T-Shirt leaving only the eyes exposed. The only other part of the persons anatomy revealed in the images was a small area of skin where there was a gap between the sleeves of clothing and where gloves were being worn.
THE PROSECUTION CASE
The prosecution case was that the hooded robber depicted in the images was the accused. At trial matching DNA was discovered on the handle of the hammer used in the robbery, along with DNA belonging to an unidentified person.
The prosecution also relied on the evidence of professor Henneberg who had examined images of the robber and the accused. Even though almost all the robber’s body was covered, based on the professor’s examination of the images the professor claimed to have identified various points of anatomical similarity between the accused and the robber. These conclusions were based entirely on the expert’s perception. No form of anthropometric measurement was used, as the images were not taken from the same angle and body-positioning. The professor’s claimed his observation did not differ from the kind of observation that could be carried out by a non-expert observer (except for the fact that his training and study in the field of anatomy meant that he had a better understanding of the shape and proportions of the human body).
Honeysett was convicted and subsequently appealed all the way to the High Court.
One of the grounds of the appeal was that the professor’s evidence should not have been admitted. It was claimed that it did not meet the conditions set out in s 79 of the Evidence Act 1995 (NSW), because his testimony was not based on ‘specialised knowledge’.
RESULT IN THE HIGH COURT.
The High Court chose to decide the appeal on the basis that the expert’s testimony regarding the shape of the heads of those depicted in the images was not based wholly or substantially on his specialised knowledge and held that the professors evidence amounted to no more than his ‘subjective impression of what he saw when he looked at the images’.
In particular the High Court said the professors evidence;
“gave the unwarranted appearance of science to the prosecution case’, and the prosecutor could have invited the jury to examine the images and find the similarities themselves”.
Mr Moussa successfully argued that the case of Honeysett applied in this particular case. The doctor in this case, very similar to Professor Henneberg’s professional qualifications and knowledge of technical terms, would have allowed a non-legally minded person or jury to simply believe him as he held himself out to be a specialist.