In the NSW Supreme Court on Tuesday, crown prosecutor Craig Everson SC argued that Christopher Michael Dawson, now 73, had killed his wife on January 8 or 9, 1982 because he desired a relationship with his former high school student, known as JC.

"By now the Crown contends that the accused had his dominoes all lined up and they were ready to fall," Mr Everson said during closing submissions.

Dawson was alleged to have tried in four ways to get out of his marriage, including moving into a flat in Manly, Sydney with JC, hiring a third party to murder his wife, selling the matrimonial home in Bayview, and moving with JC to Queensland to start a new life.

All of these plots failed, Mr Everson told Justice Ian Harrison, meaning a husband who was infatuated and besotted with his teenage lover reached a critical point of desperation and resorted to murder.

By December 25, 1981, Dawson had slid so far into moral turpitude that he had returned from his aborted trip to Queensland with JC and hid the fact that he was back from his wife, instead staying at his twin brother Paul Dawson's home, Mr Everson said.

At a marriage counselling session on January 8, the day of the alleged murder, Dawson purportedly put his hands around his wife's throat, telling her that if this did not work, he would get rid of her.

The Crown contends Dawson disposed of the body on the night of January 9 after a meeting with family friend Philip Day and Mrs Dawson's mother Helena Simms at Northbridge Baths.

Dawson is alleged to have driven through the night of January 10 to Southwest Rocks where JC was on holiday with friends, arriving there the next day and driving back with her to Sydney where she moved into the Bayview home.

This haste for the trip so soon after Mrs Dawson vanished showed Dawson's enthusiasm for JC, Mr Everson said.

Dawson's version of events, that he was a deserted husband and Mrs Dawson had simply left home without warning, was inconceivable, he told the judge.

That JC had moved into the Bayview home upon her return to Sydney, was sleeping in the matrimonial bed and was wearing Mrs Dawson's clothing did not match Dawson's claims his wife would return in a few days, the court heard.

Dawson's barrister Pauline David said her client was innocent, arguing his wife had abandoned the home and cut contact with her family.

She said police investigations into Mrs Dawson's disappearance were a quest for justice infected by the presumption Dawson was guilty.

"That quest has resulted, the defence say, in a complete disregard for the rights and for justice for Christopher Dawson," Ms David said.

Because evidence that corroborated Dawson's version of events, including telephone records and bank statements, were not investigated in a timely manner, he was at a disadvantage in defending the murder charge, the court heard.

Justice Harrison grappled with the fact that no friends or family members except for Dawson claimed they received a phone call from Mrs Dawson after January 9, 1982.

The judge also questioned how Mrs Dawson could feel optimistic after marriage counselling and then choose to leave home the very next day.

"She may have just concluded that it is just not going to work. And that's not unusual in a sense that her trust had been breached horribly by Christopher Dawson," Ms David said.

Not only had Mrs Dawson been dealt a devastating blow by her husband's choice to leave home over Christmas 1981, but she had also struggled with her own ability to take care of her children, the court heard.

"The human experience, we say, indicates that men and women do abandon their families and just because she's a mother and female that doesn't make it any less likely," Ms David said.

The trial continues.

Australian Associated Press