Shaun Mate and his three-year-old daughter were found unconscious in July 2020 in what a judge described as a vindictive act of domestic violence.
In the days leading up to the crime, Mate had bought two gas tanks, putting his plan into place after an argument with his then-wife.
Sentencing him in the Supreme Court on Friday, Justice Geraldine Davison said the impact of the 45-year-old’s offending was significant and widespread.
“Sadly, in many marriage breakdowns, when feelings are running high and the parties are feeling aggrieved and vindictive, the notion of depriving their partner of one of the greatest joys of their life can seem to be a way of wreaking revenge,” she said .
“There is a significant element of vindictiveness, planning and preparation in your offending.”
On the night of the offending, Mate had made a photo montage of the couple, which he played on the television and said to his wife, “this is what you’re going to miss out on.”
Justice Davison said he later became angry and his ex-wife began to feel unsafe and called the police.
Police arrived and the couple agreed he would stay in a room downstairs.
The judge said the girl’s mother woke up during the night to find her daughter missing from her bed and when she tried to open the door to her husband’s room he told her to “go away, we’re having a little sleep now”.
At that point, the mother heard both her daughter groan and the sound of gas and called police again.
While Mate had barricaded himself in, officers eventually gained entry where they found the girl unconscious and suffering from hypoxia.
Justice Davison said while the offending was both planned and premeditated she accepted a psychologist’s finding that Mate was suffering from a major depressive disorder at the time.
However, she said she regarded his crime as at the higher end of the scale.
“The victim was a vulnerable three-year-old child. Your planning indicates that it was premeditated offending,” the judge said.
“It was the most significant abuse of trust placed on a parent. Your intention was to take your child’s life as an act of vindictiveness against your wife thus depriving her of that child.
“Your plan failed by the good fortune of your wife waking and acting as swiftly as she did, along with the first responders.”
Justice Davison jailed Mate for 14 years and three months, reduced from 15 years because of his guilty plea.
She set a non-parole period of nine years.
If you or anyone you know needs assistance or information about domestic abuse, you can call 1800 RESPECT (1800 737 732).