Former teacher Chris Dawson attacked his wife beside the pool at their Sydney home and wrestled her in the mud before she disappeared, a court has been told.
On Tuesday, Anna Grantham said she had spoken to co-worker Lynette Dawson about her husband after seeing him angry, agitated and aggressive towards her at a market in 1980 or 1981.
In that alleged conversation, Ms Dawson described how her husband had grabbed her hair and held her face in the mud next to their swimming pool until she was gasping for breath.
"I said, 'Oh my God, he could have killed you'," Ms Grantham told the NSW Supreme Court.
"[Ms Dawson] said, 'Yes, he could easily have killed me'."
The court was played a clip of another co-worker Annette Leary recounting the poolside incident in an interview with journalist Hedley Thomas.
"Chris attacked Lyn by the swimming pool ... He'd wrestled her to the ground and had her face in the mud," Ms Leary said.
Thomas's podcast, The Teacher's Pet, was released in 2018. It discussed Ms Dawson's disappearance, and Dawson's affair and subsequent relationship with one of his high school students, known as JC.
Ms Leary, who worked with Ms Dawson and Ms Grantham at the Warriewood Children's Centre, said she had been informed of the alleged assault by one of the Dawsons' Bayview neighbours.
Dawson, 73, is accused of killing his wife and disposing of her body in January 1982 so he could have a relationship with one of his high school student, known only as JC. He has pleaded not guilty.
Ms Grantham said Ms Dawson had once caught a taxi home during the school holidays and returned to the childcare centre shaken after seeing her husband's swimming trunks and JC's bikini bottom hanging up together on the washing line.
Dawson's barrister Pauline David suggested that Ms Grantham's statements regarding the Dawsons had been contaminated over the years as she discussed the disappearance over and over.
"I'm suggesting to you that you have embellished an event to support your view that Mr Dawson is a terrible man," Ms David said.
Ms Grantham denied the accusation.
Ms Leary also called Dawson a horrible person for pursuing a schoolgirl and moving her into his marital home in her interview with Thomas, saying she knew in her heart that he had killed his wife. She said he had hoodwinked the police by lying "as hard as he could go".
Ms David questioned evidence given by Ms Leary on Monday that Ms Dawson had been seen with bruises around her throat three days before her disappearance.
Ms Leary told the court she had actually seen Ms Dawson for the last time just before Christmas 1981 when the childcare centre closed for the holidays.
She insisted that she had seen bruises on Ms Dawson's throat however, saying Dawson grabbed her during a visit to a marriage counsellor.
"How could I be wrong? I'm only telling you what Lyn told me. That's all I can do. I'm not making it up," she said.
After Ms Dawson's disappearance, Ms Leary said she had bumped into Dawson at a shopping mall with JC and his two children. At the time, he said he received a letter from his wife that she was in Queensland, the court was told.
The trial continues on Wednesday.
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