Thirty-Six Years On, What Happened To Lyn Dawson?

The teacher, the wife and the teenager lover.

It's been an enduring mystery for 36 years, and now it's gone global: what happened to Lyn Dawson?

The mother-of-two disappeared from her home just days before her husband, Chris, moved his 16-year-old lover into their house.

Decades after her disappearance the investigation has been thrown into the spotlight by the record-breaking podcast The Teacher's Pet -- the first Australian podcast to go number one in the U.S.

The weekly series -- which also reached the number one in Australia, New Zealand and the U.K. -- revolves around the mystery of what happened to Lyn, who married her high school sweetheart in  1970.

They had two daughters, Shanelle and Sherryn, and lived in Sydney's affluent northern beaches suburb of Bayview.

Sydney couple Chris Dawson and Lyn Dawson (nee Simms) married in 1970 when they were both 21 years old. Image: The Teacher's Pet

Chris had been a rugby league superstar, playing for the Newtown Jets with his twin brother, Paul, in the 1970s.

After his glittering career, he worked as a P.E. teacher Cromer High School. Chris met a student, and she became the family's babysitter. Months later they became involved in a sexual relationship.

"He would leave love notes on her school bag... he proposed marriage to her when she was still in Year 11," Hedley Thomas, the investigative journalist behind The Teacher's Pet, told Studio 10.

In 1982, Lyn confronted the student over the affair, telling her she had been "taking liberties with my husband," The Australian reported.

Lyn Dawson pictured in February, 1973. Picture: Simms family

It has been alleged by police Chris became increasingly resentful towards his wife, believing she stood in the way of a life with the student.

On the weekend of January 9, 1982, Lyn disappeared, but it took Chris six weeks to report her missing.

Chris has been at the centre of investigations from the start but has strenuously denied any involvement in Lyn's disappearance.

Police had "willful blindness" in the initial investigation said Thomas, despite the suspicious circumstances around Lyn's disappearance.

"Through the 1980s police did very little, despite urging from Lyn's friends," he said.

In 2000, police found a women's cardigan with cuts consistent with stab wounds buried in the backyard of the Dawson's family home.

A 2003 coroner's inquest found there to be "overwhelming" circumstantial evidence Chris Dawson had murdered his wife. But the NSW Director of Public Prosecutions refused to charge him, citing lack of evidence.

Image: The Teacher's Pet

"The investigations I have been doing have really just tried to reconstruct what happened, and find new evidence, and new witnesses," Thomas said on The Teacher's Pet.

"Hopefully strengthen the brief of evidence that the DPP is now considering."

The Australian announced the series would not be continuing after releasing the last episode last week -- for now.

But they said, should there be anymore breakthroughs in the investigation, the series will be continued.

NSW Police have offered a reward of $200,000 for information which leads to a conviction.