Professor John Hilton has seen many clandestine graves, but never one like that Corryn Rayney's body was exhumed from.
Yesterday, Professor Hilton, a forensic consultant who was integral in jailing serial killer Ivan Milat and identifying the dead after the Bali bombings, gave evidence at the murder trial of Perth barrister, Lloyd Rayney.
It is alleged Mr Rayney killed his wife, Corryn, at their Como home and hid her body in a bush grave located in Kings Park. His Supreme Court trial is entering its third month.
Professor Hilton told the court he'd examined many grave sites, including others in Kings Park, but said Mrs Rayney's was unusual because one end was markedly lower than the other.
The court has previously heard the configuration of the grave was significant, as placement of Mrs Rayney's head in the deeper end had sped up decomposition of the head and neck.
According to prosecutor John Agius, Mr Rayney's experience as a criminal lawyer would have made him aware of this macabre effect, which had made determination of a definitive cause of death difficult.
Professor Hilton said Mrs Rayney's death was "a difficult case to interpret", with some of his forensic colleagues under the impression her cause of death would be "un-ascertainable".
He agreed with Mr Rayney's lawyer David Edwardson that Mrs Rayney's cause of death was not "clear cut".
In disturbing testimony, Professor Hilton said it was possible Mrs Rayney had been buried alive.
He said he could not rule out her death was the result of asphyxiation after being buried in wet sand whilst unconscious. Rough placement in the grave, he said, could have caused damage to Mrs Rayney's upper vertebrae and subsequent brain swelling.
Mrs Rayney could also have died as a result of heart failure, he said, because she had coronary artery disease. The disease causes narrowing of the arteries.
He said Mrs Rayney's coronary artery disease was "very real" and "substantial", and that he'd seen people with far less marked cases die suddenly.
It was possible, he said, a sudden surge of adrenalin caused by a stressful event could result in heart failure due to the pre-existing condition.
The possibility Mrs Rayney had been sexually assaulted was again put forward by the defence.
And, according to Professor Hilton, sexual assault could not be ruled out.
He said it was possible Mrs Rayney had been the victim of a sex attack and that no evidence remained, agreeing with the defence assertion the state of her clothes after her exhumation pointed towards a possible assault.
When Mrs Rayney's body was recovered, her jeans and belt were undone and teeth from the jean's zipper were missing.
Professor Hilton said Mrs Rayney's lack of visible injuries – which included a strange bruise on her tongue and chipped tooth - did not exclude sexual assault.
He also agreed Mrs Rayney could have suffered a heart attack as a result of an attempted sexual assault given her pre-existing coronary artery disease.
The trial before Justice Brian Martin continues.