Two witnesses giving evidence in the Chris Dawson murder trial have testified that his second wife shared suspicions that he had killed his first wife Lynette.
Toni Melrose-Mikeska said she had a conversation in 1990 with Chris Dawson's second wife, known as JC, on the day JC left Mr Dawson after six years of marriage, to travel back to Sydney with their young daughter.
"She said 'I think he murdered his first wife'," Ms Melrose-Mikeska told the court on Tuesday.
It's the Crown case that the former Sydney school teacher killed Ms Dawson in January 1982 in order to pursue an "unfettered relationship" with JC, who was 16 years old and a babysitter for the family at the time.
Ms Dawson has not been seen since, and her body has never been found.
Ms Melrose-Mikeska said JC told her she was planning to tell the police about her theory.
"She said that if she doesn't make it, that I was to go to the police and tell them some information that she relayed to me ... that she and Chris had gone to, I'm sure it was a pub ... and he spoke to a man at the pub. She saw him hand him an envelope and then a little while later Lynette disappeared."
In her evidence last month, JC told the court that towards the end of 1981, Mr Dawson drove her to an unfamiliar location and spent 15 to 20 minutes inside while she waited in the car.
"He said 'I went inside to get a hitman to kill Lyn, but I decided not to do it because innocent people could be killed, could be hurt'," she said.
On Tuesday, a second friend of JC, Karen Longhurst, told the court JC had relayed a similar concern to her in the lead-up to the separation.
"She said to me should anything happen to her, I was to go to the police because she thought his first wife had been killed."
Ms Melrose-Mikeska said she believed Mr Dawson was a "very controlling" person, and that he had insisted on inspecting an indoor cricket venue before granting JC permission to play there.
"We just sort of waited in the foyer, and he scouted about the venue to sort of give her permission to play. That's not normal, to do that," she told the court.
The court also heard from a witness who attended Cromer High School alongside JC in the 1980s.
The man, known as RH, said he had been "interested" in JC and sought advice from Mr Dawson, his PE teacher and rugby league coach at the time, about how to "get closer" to her.
"The discussions were about how to engage in conversation, I guess, and build up to a point of asking her to go out," he told the court.
RH said the two of them came up with a "ruse" whereby he would turn up at JC's house on a Sunday morning when Mr Dawson was there.
He said the plan was for Mr Dawson to excuse himself and leave the high schoolers alone together, but that when the day came, it played out very differently.
"What happened when you got as close as you did to the home?" Crown Prosecutor Craig Everson asked.
"I went to the door, and the plan had changed, and I was encouraged to leave," RH replied.
"I was expecting [JC] to greet me, instead Chris greeted me and said words to the effect of, 'the plan's aborted'.
The trial before Justice Ian Harrison continues.
