A JUDGE has criticised a police investigation into the killing of a Scot in Australia as he sentenced her attacker to eight-and-a-half years in prison.

Justice John McKechnie said pensioner Ronald Pennington, 82, could die behind bars after being convicted of killing Cariad Anderson-Slater and concealing her remains in his garden for almost 20 years.

Mrs Anderson-Slater, 42, originally of Elgin, Moray, went missing in the early hours of July 13, 1992 – just two years after she moved to Australia with her husband and son.

Her remains were found by workers digging up the garden of Pennington's former home in Perth, Western Australia, last February and the case was then reopened by police.

Justice McKechnie claimed the initial police investigation was incompetent and focused too heavily on Mrs Anderson-Slater's husband, David Slater.

He said: "The police investigation in 2011 seems to be very thorough and competent. Neither of those words can be used in 1992.

"The police investigation then seemed to focus on Mr Slater and seemed to ignore the person who was likely to last see her alive."

The judge added: "Had the police taken a more objective view back in 1992, then maybe David Slater would not have had to endure two decades of suspicion."

Mrs Anderson-Slater, who regularly went on alcoholic binges, was last seen alive by a taxi driver who dropped her off at Pennington's home on the day she disappeared.

Pennington claimed he did not let her in but in fact concealed her body for years as her family agonised over where she was. When her remains were eventually discovered, there was no indication of how she died.

The pensioner was originally tried for murder, but on Monday jurors convicted him of the lesser charge of manslaughter.

Outside court yesterday, Mrs Anderson-Slater's daughter Melanie MacEachen – who flew from Scotland to Perth for the trial – said she felt her mother would be happy now.

She said: "Last night I really felt something lifted, I felt that somehow, somewhere, she is happy now, she is dancing."

Pennington's defence lawyer Linda Black told the court her client remains adamant he was not responsible for the death and intends to lodge an appeal against his conviction.

However, Justice McKechnie said the conviction was to be considered final unless a Court of Appeal found that he had made any mistakes in his direction to the jury.

The judge added that the evidence in the case had been "more than sufficient" and it was concerning that Pennington had tried to blame Mr Slater for the crime.

He said: "He did it, he has always known that he did it, but his instructions were to make a considerable attack on an innocent."