Chris Dawson arrives at court on August 30 in Sydney, Australia.
Sydney CNN  — 

A former high school teacher found guilty of killing his wife in one of Australia’s longest cold cases has been sentenced to 24 years in prison.

New South Wales Supreme Court Justice Ian Harrison handed down the sentence on Friday, having found Chris Dawson guilty in August of murdering his wife Lynette in 1982.

Harrison, the sole judge hearing the case, found that Dawson had killed his wife so he could start a new life with a then 16-year-old student, who babysat for the family.

The crime saga inspired a 2018 podcast by Australian investigative journalist Hedley Thomas called “Teacher’s Pet,” which gained a cult following.

The verdict came despite a lack of physical evidence of Dawson’s involvement in his wife’s presumed death. Her body has never been found.

While the sentence carries a no-parole period of 18 years, a new “no body, no parole” state law means Dawson, 74, won’t be eligible for early release as long as the body remains missing.

The “Teacher’s Pet” podcast examined the police investigation and gathered new evidence including testimony that Dawson, a professional rugby player turned teacher, had been having sex with one of his students when his wife disappeared 40 years ago.

Dawson had pleaded not guilty, instead claiming his wife had walked out on him and their two young children when they were just 2 and 4 years old.

CNN’s Hilary Whiteman contributed to this report.