A NSW teenager has been jailed for shooting his sleeping father dead on an "ordinary and unremarkable evening" after the family had shared a meal and watched television.
The youth, who cannot be named, was on Friday sentenced to at least 11 years and seven months in jail for charges including murdering his father on April 23, 2008 at his property near Mudgee.
In the NSW Supreme Court in Sydney, Justice Peter Johnson said he believed the boy, then aged 17, intended to kill his father, and rejected a suggestion he only meant to scare him.
Although there was no evidence of a history of physical or emotional abuse by the "relatively strict" father, the judge said the teenager perceived he had been treated unfairly.
But his judgment had been affected at the time of the shooting by untreated juvenile bipolar disorder and depression, Justice Johnson said.
"The offence was committed on what might be considered to be an ordinary and unremarkable evening where members of a family had dinner, watched television and then went to bed.
"The explanation for this bizarre crime lies in the offender's wish to harm and kill his father in circumstances where an undiagnosed and untreated mental disorder had an impact upon his judgment."
According to an agreed statement of facts, the youth loaded and cocked a shotgun, and lay with it while watching television.
He then went into his father's bedroom and fired a shot about 50cm or one metre from his head, the judge said.
The teenager's brother came into the room and saw their 47-year-old father was dead.
The pair went into Mudgee and withdrew $2,000 from their father's bank account in a "state of panic".
When they returned to the property the brother went to bed, while the teenager stayed up and watched television before they fled the property the next morning in their father's work car.
That morning the teenager called his mother, who lived in Sydney, to tell her what happened and the pair eventually went to Castle Hill police station, where they were arrested and charged.
When police earlier called the boys on a mobile phone, the teenager told them his father had treated him and his brother badly for years and said, "I don't know, for some reason I just snapped".
Justice Johnson said the father had been strict with his sons, which could not be criticised, but there had been no disagreements on that night or in the days prior.
The teenager pleaded guilty to his father's murder and to aggravated break, enter and steal, relating to the theft of several firearms, including the murder weapon, the day before.
He also admitted to obtaining money by deception, relating to the ATM withdrawals.
The brother was last year sentenced to at least four years and nine months' jail on several charges, including being an accessary after the fact to murder.
The teenager sentenced on Friday will be eligible for parole in November 2020 and his maximum term expires on December 23, 2025.