HIGH profile barrister Lloyd Rayney has been found not guilty of killing his estranged wife, Corryn, following one of the most high-profile murder trials in WA history.

The prosecution alleged Mr Rayney murdered the former Supreme Court registrar at their suburban home after her weekly dance class on August 7, 2007 before burying her head-first in a grave at Kings Park.

However, Justice Brian Martin, QC, dismissed the allegation in the WA Supreme Court judge-alone trial, ending Mr Rayney's five-year ordeal to prove his innocence.

Mr Rayney, 50, looked relieved as the judge pronounced him not guilty of wilful murder and an alternative count of manslaughter. He would have long faced long prison terms for either if convicted.

READ THE JUDGMENT SUMMARY HERE

Justice Martin took the unusual step of addressing Mrs Rayney's father, Ernest da Silva, as he handed down his verdict.

Justice Martin chokes back tears before verdict

Just before declaring Mr Rayney not guilty, Justice Martin choked back tears as he thanked Mr da Silva for "behaving impeccably and with dignity" throughout the four month trial.

Later, outside the court, Mrs Rayney's sister Sharon Coutinho told reporters the family would continue to seek justice for Mrs Rayney, 44.

Mr Rayney left court accompanied by his youngest daughter Sarah and other family members to chaotic scenes, where he addressed a media throng, telling them that the troubling part of the case was that his wife's killer had not been found.

He asked that he and his daughter be allowed to leave in peace.

"This is still unsolved and this is an extraordinarily hard thing for my family to accept," he said.

Just after 1.30pm Mr Rayney drove into his Como home where family, friends and legal colleagues had gathered to celebrate the verdict.

Corryn's sister says family will continue fight for justice

Mrs Rayney's family left the courtroom about 15 minutes after Mr Rayney. Her sister Sharon Coutinho read a prepared statement to reporters on the steps of the court house.

She thanked the police officers who had investigated her sister's death for their "unconditional support".

"We would like to express our sincere appreciation for their determination and perseverance over the last five years in seeking justice for Corryn.

Mrs Coutinho also thanked prosecutors involved in the case for "finally giving Corryn a voice" and for support of members of the public.

"Our quest for seeking justice for Corryn will continue," she said.

In a verdict, delivered over more than half an hour, Justice Martin said the circumstances of the case involved a tragedy involving many people.

"Some of these people are likely to be distressed by my verdict," he said.

State case 'beset by improbabilities and uncertainties'

But in finding Mr Rayney not guilty, Justice Martin said the State's case against Mr Rayney was "beset by improbabilities and uncertainties".

"Crucial evidence is lacking and the absence of evidence tells strongly against the State," he said.

"Endeavours by the State to fill critical gaps and explain away improbabilities are primarily no more than speculation without foundation in the evidence."

Among the judge's findings today were:

* That Mrs Rayney was attacked at the family home in Como on the night of August 7, 2007, but the evidence did not prove beyond a reasonable doubt that Mr Rayney was the killer.

* That Mrs Rayney was subjected to a violent assault that caused trauma to her interveterebral discs and brain, but the injuries were probably not life threatening.

* Whoever attacked Mrs Rayney rendered her unconscious and decided to bury her and transport her to Kings Park in the back of her own car.

* Pollen in Mrs Rayney's nasal passages show Mrs Rayney probably took her last breaths near her Kings Park grave.

* Mrs Rayney was either killed before being placed in the grave or was alive when she was buried.

Mr Rayney sat impassively through most of the judge's address, but began to look visibly relieved towards the end. The police officer who headed the investigation into Mrs Rayney's death, Carlos Corriea had his head resting on his hands, while Mr Da Silva covered his face.

Justice Martin said although there had been claims by Mr Rayney's lawyers that the police had conducted a narrow investigation, that was not the case.

Some police conduct 'unacceptable'

"While there were instances of unacceptable conduct by some investigators ranging from inappropriate to reprehensible, there is no evidence that lines of inquiry were not properly investigated."

He also addressed the evidence that Mr Rayney had tapped the family's home telephone to allegedly listen in on his wife's telephone calls as their marriage fell apart. Justice Martin said Mr Rayney would have known the telephone interception was illegal.

"The accused knew that he was setting out to engage in illegal telephone tapping and he incurred expenses of approximately $2000 in order to achieve his purpose of obtaining what colloquially might be called 'inside information'," he said.

Of events of the night of August 7, 2007, Justice Martin said he accepted that Mrs Rayney left her boot scooting class at about 9.30pm intent on meeting her husband to discuss his financial affairs.

"The totality of the evidence, including forensic evidence, has satisfied me that the deceased arrived home at about 9.45pm or a little earlier," he said.

But he said the fact that Mrs Rayney was attacked near the family home did not prove Mr Rayney had been her killer.

Corryn attacked in front yard or verge - Justice Martin

"I am satisfied from the forensic evidence that the deceased was attacked in the front yard of her home or on the verge immediately outside her home," he said.

"I am satisfied that the deceased was attacked and was in difficulty on the ground when the two seed pods from the Liquidambar tree in the front yard at Como became attached to her hair….it is the next step of proving that it was the accused who attacked the deceased that the State case experiences difficulties."

Justice Martin noted Mr Rayney had weighed less than his wife, had a bad back and was in "soft physical condition" at the time Mrs Rayney was killed and buried.

He said Mrs Rayney could have been the victim of a sexual attack.

"The State contended it is so highly unlikely that someone would attack the deceased outside her home that such a possibility should be rejected," he said. "Ordinarily the community hopes that such events do not happen, but on occasions the community is shocked to learn that such attacks do occur."

How a dinner place card bearing Mr Rayney's name came to be found near the gravesite remained a mystery. "Strange events happen for odd reasons," he said.

"Mysteries emanating from evidence given in criminal cases remain unsolved."