The case of Lynette Dawson's disappearance and murder has been closed after more than four decades as the High Court refuses to entertain her husband's challenge to his conviction.
Chris Dawson, 76, killed his wife and disposed of her body in January 1982 because of his infatuation with a teenage female PE student.
That young girl swiftly moved into Dawson's home after he murdered his wife, NSW Supreme Court Justice Ian Harrison found in August 2022.
The former teacher was sentenced to a maximum of 24 years for the crime.
The NSW Court of Appeal rejected his challenge to his murder conviction in June 2024, finding that there was no miscarriage of justice despite errors in Justice Harrison's decision.
Dawson then took the matter to the High Court where a panel of six judges shot down his final bid on Thursday.
"There is no reason to doubt the correctness of the decision of the Court of Criminal Appeal including its dismissal of the appeal," the judges wrote.
"Accordingly, it would be futile to grant an extension of time (to appeal)."
Earlier in June, Dawson also lost his challenge to a separate carnal knowledge conviction in the NSW Court of Appeal.
That case upheld findings by the state's District Court that the ex-teacher had engaged in unlawful sexual activity with the student who eventually moved into his home before she turned 17.
The carnal knowledge sentence added one year to his non-parole period which expires in 2040.
1800 RESPECT (1800 737 732)
National Sexual Abuse and Redress Support Service 1800 211 028
Lifeline 13 11 14
Men's Referral Service 1300 766 491
