Ronald Leslie Pennington, 85, is charged with the manslaughter of Cariad Anderson-Slater, whose remains were found in the garden of his former home.
Mrs Anderson-Slater, originally from Elgin, Moray, moved to Australia in 1990 before vanishing two years later, aged 42. Her whereabouts remained a mystery until her body was discovered in 2011 when workers dug up the garden of Pennington's former home in Perth, Western Australia.
Pennington was found guilty of the killing in 2012, but his conviction was quashed when a court of appeal found the judge had misdirected the jury. He was then retried in 2013, but jurors failed to reach a verdict and the case was abandoned. The pensioner's third trial began on Tuesday in the Supreme Court of Western Australia.
In opening speeches, prosecutor Justin Whalley said Ms Anderson-Slater was a binge drinker who often disappeared for days at a time. He said her husband, David Slater, was concerned about her drinking and the couple, who had only lived in Perth for a couple of months, did not have many friends. The court heard that Pennington, then aged 63, invited the couple to dinner on the night of Mrs Anderson-Slater's disappearance.
Mr Whalley said when the couple returned home they argued about the deceased's drinking, culminating in Mr Slater ripping the phone out of the wall. The last time Mr Slater saw his wife alive was when she went to a neighbour's house.
Mr Whalley told the court that Mrs Anderson-Slater then caught a taxi to Pennington's house and "disappeared into thin air".
Pennington left Western Australia soon after and it was not until his former property was being excavated that Ms Anderson-Slater's remains were found.
Pennington, who had moved to Tasmania, was then extradited to Perth to face the charge.
The retrial continues.