Victoria-based Robert Farquharson 38, was taking his children back to his ex-wife's house two years ago on Father's day 2005, when his car supposedly ran off the road and into the water. The three boys then aged nine, seven and two, drowned.
Ever since accused, Farquharson has denied killing his sons; blaming a coughing fit and subsequent blacking out for the incident.
Yet, the prosecution has been able to prove the contrary, with a spate of police tests. Testing of the tire marks show that at no time was the car out of control. In fact it has been proved that the car was steered in three distinct maneuvers to avoid trees at the dam's edge.
According to prosecution QC Jeremy Rapke, the incident was a wicked act, which turned on its head the notion a father, would do anything to protect his children.
The jury has also heard Farquharson was involved in a bitter separation from his wife. Most importantly, there is a testimony against Farquharson by his friend Gregory King.
In mid-2005, while outside a Winchelsea fish and chip shop, Farquharson complained about his estranged wife, Cindy, to King. "I get the shit car, she gets to drive around in the good car. She's going to pay big-time for this ... She's not going to do that to me and get away with it", King recollects Farquharson saying.
Rapke told the court that, when King asked what he would do, Farquharson replied: "Take away the most important thing for her." And he motioned his head towards the shop and the children.
Rapke said Farquharson then talked about an accident involving a dam, in which the children would drown while he escaped. It would be Father's Day, so that everyone would remember it, and so that he would be the last one to have his children, not his wife. He said Cindy would suffer every Father's Day for the rest of her life.
At that point King's children walked over and the conversation ended, says Rapke.
According to sources, Farquharson has had a history of depression following the marital break-up and his former wife's new relationship. He has been treated with anti-depressants and has attended counseling.
The trial is still running before Justice Philip Cummins.