The 74-year-old former rugby league player faced the NSW Supreme Court in his prison greens on Thursday after a judge found he had killed his wife and disposed of her body in January 1982 because of an infatuation with the family babysitter.

Dawson had been taken to Silverwater prison after Tuesday’s verdict and had suffered “constant threats” to his life while there, his lawyer Greg Walsh told Justice Ian Harrison.

Lynette Dawson’s body has never been found despite despite extensive searches of the Bayview property the couple once shared on Sydney’s northern beaches.

The judge found the then-schoolteacher murdered his wife because he held a deep animosity towards her as an obstacle to his relationship with JC, a former student, who he was obsessed with.

Dawson’s lies to police and family members were relied on in the judgment to show guilt that he had indeed killed his loving, committed wife.

On Tuesday, Walsh said an appeal would be filed.

He also told reporters the former Newtown Jets rugby league player was suffering physical health problems and cognitive issues, including a diagnosis of dementia.

Meanwhile, Homicide Squad commander Danny Doherty said the police investigation was not over despite the welcome conviction.

“Our efforts and inquiries to find Lyn’s remains are ongoing, and we once again urge anyone with information which may assist us to get in touch,” he said in a statement on Thursday.

“After a journey of more than 40 years, we hope to give Lyn’s family the chance to say goodbye.”

A sentence hearing will be held on November 11.