TRUE CRIME: How Robert Farquharson was convicted of the murder of his three sons.

Father’s Day 2005 wasn’t one of Robert Farquharson‘s scheduled access weekends, but his ex-wife Cindy Gambino allowed him to spend it with their three sons – Jai, 10, Tyler, seven and Bailey, two.

As the time for him to return them drew closer, Gambino waited at her home with her new partner Stephen Moules’ son Zach.

Ten minutes after the appointed arrival time, she saw a car draw up to the driveway – but it wasn’t Farquharson’s.

In the white commodore was her ex-husband and two strange men.

Listen to what happened next on Australian True Crime With Meshel Laurie and Emily Webb podcast.

“‘The kids are in the car. They’re in the water,'” she recalled in court him saying as he stood drenched on her doorstep.

She immediately called Moules before jumping in her car with Zach and Farquharson, who gave directions to where the car was.

On his way back to Winchelsea, 36 year old Farquharson drove his car into an icy dam, killing all three of his children.

For a long time, Gambino believed her ex-husband when he said it was an accident, after he had a coughing fit, blacked out and woke to find the car in the farm dam.

Almost two years after their death, Farquharson stood trial for the murder of Jai, Tyler and Bailey.

After six weeks of evidence and three days of deliberation, the jury found the cleaner guilty.

He was sentenced to three terms of life imprisonment without parole - a term he would eventually successfully appeal and get overturned, before a retrial found him guilty again in 2010.

Robert Farquharson will pay an undisclosed amount in compensation to his ex-wife: https://t.co/6Bx8SaBss7 #9News pic.twitter.com/kSDZkWfsI7

— Nine News Melbourne (@9NewsMelb) November 30, 2015

The case made headlines all over Australia and has been the subject of two books - Helen Garner's The House of Grief and On Father's Day by Megan Norris.

Norris joined True Crime podcast hosts Meshel Laurie and crime writer Emily Webb to take a deeper look into the tragic case and determine whether it was an accident as Farquharson still maintains, or the ultimate form of family violence.

For Norris, there's no question that his intention was to punish Cindy forever, after she ended their relationship in 2004.

She says the first warning bells lie in his immediate account after the event, calling his story "an evolving one".

"In the cold light of day you can see that he was figuring it out," she told Laurie and Webb.

The first people he spoke to, Shane Atkinson and Tony McClelland, two young Winchelsea men who Farquharson flagged down were initially told it had been a terrible accident, claiming he must have done wheel-bearing, then woke up in the water.

Cindy Gambino, whose three sons drowned when their dad Robert Farquharson… http://t.co/2hGHKZHF0M #InfoNdoroTweet pic.twitter.com/PJBkNLDGrw

— PAKDE Sosmed® (@totosmongi) October 9, 2015

"Then as he was getting his lift back into Winchelsea to break the news in person because he needed to be up close and personal to see the horrific effect this had on his ex-wife, he said in the car he had a coughing fit and must have blacked out and ended up in the water," says Norris.

When the ambulance and paramedics arrived on the scene to treat him, his tune had changed considerably and he told them he'd had a chest pain.

"He had none of the symptoms they would have expected to find in someone who had had not just a coughing fit but one severe enough to cause a blackout.. There was no crackling, there was no chestiness, there was not even a wheeze," says Norris.

"And not once during the examination they conducted at the scene did he even cough. They had to ask him to cough and when he coughed it was a dry unproductive cough rather than a chesty wheezy cough that was so severe it caused a blackout.

"So this sort of version that he gave was was already suss."

He told a policeman at the scene a different story, carrying on about the wheel-bearing again before becoming more elaborate when two police officers came to interview him at Geelong hospital, where he was taken to be treated for shock and hypothermia.

"That's when he was saying 'I don't know what happened, Jai must have tried to open the door. I got out of the car first and thought I was in a ditch [gesturing] the water is up to my chest'," says Norris.

He then blamed his oldest son Jai for sinking the car, an explanation that played a big part of his defence in court before being disproven.

"Then he went to get out and then he realised he was in the dam, so the story has changed again. He was going to walk around to help the kids out but then he had to swim around. Then he changed the story again and said the car started to sink when Jai opened the door," says Norris.

For a closer look at the case and all the details you might have missed, listen to Mamamia's new Australian true crime podcast, True Crime.

To find a book mentioned in this, or any other Mamamia podcast, go to apple.co/mamamia where you'll find all of our shows and books by our guests in one place.