Lloyd Rayney has labelled the police investigation into his estranged wife's murder a nine-year farce, saying it remains a solvable crime despite the cold case review being wound up with no results.
Corryn Rayney, a WA Supreme Court registrar, disappeared on August 7, 2007 and was found days later, buried head-first in a shallow grave at Kings Park.
Mr Rayney was acquitted of her murder in 2012, with Justice Brian Martin concluding she had been randomly attacked outside their Como family home in a violent, possibly sexually motivated assault.
In 2014, Mr Rayney called for a cold case review, which commenced some nine months later.
But on Thursday, Police Commissioner Karl O'Callaghan said there was insufficient evidence to charge anyone over her death.
Mr O'Callaghan said it was terribly disappointing the culprit - or culprits - had not been identified.
"We deeply regret that despite all of our efforts, we have not been able to find those much-needed answers," he said.
"Not every police investigation ends with a prosecution and I am comfortable that Operation Delve has exhausted all current, available leads."
Mr Rayney, a barrister, said police did not tell him or their daughters Caitlyn and Sarah about the decision to end the fresh investigation and declare the case an unsolved homicide.
"Nine years later, to learn from a reporter of what the police decided was astonishing," he told AAP.
"Even worse, Corryn's closest family - our children - learnt about this from the internet.
"Throughout the nine years that this farce has been going on, police have treated our children in the most despicable ways."
Mr O'Callaghan confirmed police internal affairs had dismissed a complaint from Mr Rayney about the conduct of officers during Operation Delve.
"None of the complaints were sustained. Investigations have been completed," the commissioner said.
Mr Rayney, who is suing the WA government for defamation after being named by a senior policeman in 2007 as "the prime and only suspect", believes the crime can still be solved.
That's despite Mr O'Callaghan saying it was the "unfortunate reality of many cold case inquiries that the passage of time has taken its toll".
"Corryn's murder was always a solvable crime and it still is," Mr Rayney said.
"The evidence is all there."
Mr O'Callaghan said the case had been referred to the coroner and fresh evidence will be required for police to pursue any criminal charges.
"The file will always remain open. Special crime squad will have access to it now so any new material emerging will be thoroughly investigated," Mr O'Callaghan said.
During Mr Rayney's 2012 trial, his defence team named convicted sex offender Allon Mitchell Lacco as a potential suspect.
They questioned why police did not further investigate Lacco and his housemate Ivin Eades, whose DNA matched a cigarette butt found on a footpath outside the Rayneys' home.
