The babysitter and woman who eventually married Christopher Michael Dawson threatened his first wife Lynette and had reason to see her killed, a judge has heard.

In the ongoing murder trial against Dawson, 73, an intercepted phone call between himself and his twin brother Paul from March 1999 was played to the court.

In that call, Paul Dawson is heard saying that the babysitter, known only as JC, had motive to kill Mrs Dawson, who disappeared in January 1982.

“If Lyn had been murdered, (JC) had the motive. (JC) had more to gain and (JC) did gain more than Chris ever gained from their relationship,” Paul Dawson told the NSW Supreme Court.

Dawson has been accused of murdering his wife and disposing of her body in January 1982 so he could have an unfettered relationship with JC. He has pleaded not guilty to the charge and claims Mrs Dawson left home at the time due to marital issues and never returned.

JC and Dawson married in 1984 and separated in 1990.

JC was a ‘cruel mother’ to Dawson’s daughters

Paul Dawson told Justice Ian Harrison that, at a birthday party for one of Mrs Dawson’s daughters, JC had threatened to get rid of her if she got in her way.

JC was a cruel mother to Dawson’s two daughters after the marriage, refusing to pick them up from school, banning the use of the word ‘family’ when referring to them, and tying their hair back so hard their scalps bled, the court heard.

“She really treated them as outcasts in their own home,” Paul Dawson said.

Police claims Dawson had anything to do with the alleged murder of his wife were preposterous, he said.

He told the court that media reports saying his brother was violent were outrageous because he was the least violent person he’d ever met.

Brother dismisses claims of forged signature

He also dismissed claims his wife Marilyn Dawson had been seen practising how to forge Lynette Dawson’s signature after she disappeared as “complete and utter garbage”. The court previously heard the signature was forged on a life insurance policy taken out under Mrs Dawson’s name.

He told the court he didn’t question Mrs Dawson taking some time away from the marriage because his brother had done the same in December 1981, when he had driven north towards Queensland with JC.

After his wife disappeared, Dawson drove up to the Central Coast several times to look for her, the court heard.

Mr Dawson admitted he was not in favour of his brother’s relationship with JC when they first started dating in late 1981.

Dawson did most of mothering, fathering

Mrs Dawson was a good mother, but was not overly affectionate towards her children, he said. She felt they did not need her as much as the kids she looked after as a nurse and childminder, because her husband was hands-on and would take care of most of the mothering and fathering.

Paul Dawson’s babysitter from 1980 and 1981 also gave evidence on Thursday. The woman, who can only be referred to as SO, claimed that during car trips in Sydney, she heard Chris Dawson refer to his wife as a bitch and saying she had to go.

She said that during another car trip with the Dawson twins and JC, Dawson got out of the car, handed a package to a man outside a building, and returned saying that something had been “taken care of”.

JC told the court last month that Dawson had attempted to hire a hitman to kill his wife but had changed his mind. In that version of the story, only Dawson and her were in the vehicle.

At the end of 1981 or the beginning of 1982, SO claimed Paul Dawson had told her that his family would need to urgently move to Queensland.

“He said he was moving and something horrible had happened and he needed to leave as soon as possible.”

When Dawson’s barrister Pauline David pointed out that the Dawsons had only moved to the Gold Coast in 1984, OS said they had been able to wait because nothing happened despite police looking into the disappearance.

The trial continues on Friday.

-AAP