At a living wake for a family friend, Christopher Michael Dawson said his wife was living in a commune west of Sydney more than 25 years after she disappeared, a judge has been told.
Giving evidence at Dawson's murder trial on Monday, a woman said she bumped into twin brothers Chris and Paul Dawson at a wake for Phillip Day who was sick with cancer and died in 2007.
She said Dawson told her his wife Lynette had left home and was living in a Blue Mountains commune at the time. The woman asked how a wife could just up and leave her kids.
"Paul said something along the lines of, 'she was a little bit crazy'," she told Justice Ian Harrison.
The witness, whose husband went to Sydney Boys High School with the Dawsons, is a professional recruiter. She said she knew body language and described the Dawson twins' behaviour as "creepy" because of the way they sat so close together.
"I think Chris was checking with his older twin that he was saying the right thing. That was the impression that I got," she said.
Dawson, now 73, is accused of murdering his wife and disposing of her body in January 1982 so he could have an unfettered relationship with a woman known as JC who was his babysitter and former high school student.
He has pleaded not guilty to the charge.
Former police officer Ian Kennedy also went to Sydney Boys. He told the court he may have attended a school reunion with the Dawsons in 1985 but denied saying Mrs Dawson was seen living in New Zealand at the time.
"I had no part in any investigation into Lynette's disappearance at all," he said.
Paul Dawson has previously told the court that his brother was pulled aside by Mr Kennedy at the reunion and told of his wife's whereabouts.
Dawson's former neighbour Malcolm Downy testified that he had seen Mrs Dawson "upset and nervy" when she knocked on his rear laundry door shortly before her disappearance.
"She looked stressed and she didn't have the kids with her. That was strange. That woman never went without her children," he said.
The NSW Supreme Court trial continues.
