An Adelaide man who killed another motorist during an extreme episode of road rage said "I warned you" to his victim before stabbing him through the heart, a court has heard.
Benjamin Joshua George, 27, pleaded guilty earlier this year to murdering 34-year-old Troy James McLean at Salisbury in November 2017.
During a pre-sentencing hearing, the Supreme Court heard an altercation erupted after Mr McLean accidentally nudged his car into the back of George's vehicle at the intersection of Waterloo Corner Road and Salisbury Highway.
It heard George got out of his car and said to Mr McLean "I warned you" before stabbing him twice, once in the chest and another through his heart.
Mr McLean tried to drive himself to the Lyell McEwin Hospital, in Elizabeth Vale, but crashed into a parked car on the way.
He was transferred to the Royal Adelaide Hospital in a serious condition and died from his injuries three days later.
Defence lawyer Heath Barklay SC told the court his client was affected by a "cocktail of drugs" at the time of the altercation.
"There wasn't too much going through Mr George's mind at the time he caused these injuries," he said.
"He had been up for many days, was heavily affected by drugs and he accepts that he must have intended to cause grievous bodily harm.
"It's fair to say that he was extremely affected by drugs and by lack of sleep and has very little recollection of the events.
"The events objectively and the response came out of nowhere."
George was living the 'life of a hermit'
Mr Barklay said George's mental health had been declining in the months leading up to the offending and that he had been living the "life of a hermit" and was too anxious to leave his house.
The court heard photos of a bloodied knife taken on the day of the attack were found on George's mobile phone, but police had been unable to locate the knife.
Further sentencing submissions were adjourned until October to allow time for a psychiatric report to be completed.
The court will also hear four victim impact statements at the next hearing.
