Convicted murderer Chris Dawson has been found guilty of unlawful carnal knowledge.
District Court of NSW judge Sarah Huggett on Wednesday convicted Dawson of carnal knowledge as a teacher of a girl aged over 10 and under 17.
Carnal knowledge is a historic charge relating to sexual intercourse with a minor.
The now 74-year-old, who was convicted of murder in 2022, had pleaded not guilty.
Dawson's judge-alone trial was told he groomed the 16-year-old student in his sports class, who had a troubled home life and turned to him for support.
The prosecution said Dawson engaged in sexual activity with the student identified only as 'AB' between July and December 1980, while she was aged 16 and attending the school where he worked on Sydney's northern beaches.
Dawson does not deny having sex with AB, but his lawyer argued the alleged sexual activity began in 1981, after she had turned 17 and was no longer his student.
Watch: Lynette's brother, Greg Simms and Chris Dawson's lawyer speak outside court. Post continues below.
Earlier in the trial, AB said Dawson first became interested in her after he found a topless photo of her taken at a picnic when she was 15.
Detective Sergeant Laura Beacroft - who led Strike Force Southwood investigations into sexual abuse of students at northern beaches high schools - told the court the Department of Education did not uncover any records of complaints filed against Dawson while he was employed at Cromer High School between 1979 and 1983.
Neither Dawson nor his twin brother Paul, who the court heard kissed and cuddled with schoolgirls in a pool, have given evidence in the trial.
Evidence in the trial at Downing Centre District Court wrapped in early June with the judge delivering her verdict three weeks later.
In her verdict, Judge Sarah Huggett said AB was "a thoughtful witness who gave her evidence in a matter-of-fact and forthright way". The judge also referred to Dawson's "grooming process" during the verdict speech.
"She appeared willing to provide as much detail as she could but did not appear to embellish her evidence. While there was obviously a relationship between the complainant and the accused, which commenced in circumstances that she believed involved grooming when she was vulnerable … I did not form an impression that the complainant was motivated by a desire to give deliberately false evidence."
Dawson is already expected to spend the rest of his life in jail for the murder of his wife Lynette who was last seen more than four decades ago.
In January 1982, he murdered Lynette, a judge finding he was motivated by a desire to pursue an unfettered relationship with a student. They married two years later.
Dawson was sentenced to 24 years for the murder. He has said he intends to appeal the murder conviction.
Dawson will appear for sentencing for the carnal knowledge charge on September 15.
With AAP.
Feature Image: AAP.