The groaning noises Peter Dunne made after being deliberately hit by a car were thought to be the ramblings of a neighbour - instead that man was behind the wheel.
Thomas Hill pleaded guilty on Monday to the manslaughter of Dr Dunne who was struck by a vehicle in Brisbane's Tarragindi suburb in February 2019.
In the months before the hit-and-run Hill, now 37, had become angrier and more confrontational thinking his neighbours were bullying, gossiping and out to get him, Brisbane Supreme Court was told.
From October 2018, Hill and his mother slept in their small car, returning sporadically to their Tarragindi house in the early morning, to avoid interactions with the neighbours.
The victim and Hill first encountered one another weeks before the incident when the accused was behaving in an angry and agitated way towards his mother, prosecutor Elizabeth Kelso said.
Hill perceived Dr Dunne was staring at him, while his mother thought the doctor called her son an "idiot".
Hill ran at Dr Dunne, pushing him and yelling abuse.
Dr Dunne was again on his regular 4am run on February 18 when the Hills drove past in separate cars.
Hill's mother thought Dr Dunne called out "idiot or something" before shining his torch into her car.
"It seems those actions are what sparked the defendant to become angry and to decide to confront Dr Dunne," Ms Kelso said.
Hill did a u-turn, accelerated, reversed and then struck the doctor on the calf with the car before driving off.
Medical evidence suggested Dr Dunne fell, hitting his head with considerable force on the road after his foot became caught somehow in the car.
Neighbours initially thought Hill was making noises on the street before calling emergency services about 5am.
Instead police found Dr Dunne moaning and groaning. He was conscious but unable to say what happened.
Dr Dunne was taken to hospital with a catastrophic brain injury, before dying six weeks later.
Police installed a listening device in Hill's car, capturing his explanations about why he confronted Dr Dunne.
"I can guarantee you now, if he didn't prolongingly stare ... I would never have chased him," he said.
Hill had been mentally unwell for years with his behaviour escalating before the incident, defence barrister Gregory McGuire told the court.
Neighbours had reported Hill yelling in the street that he was being stalked and lies were being told about him, Mr McGuire said.
Hill has been in custody, initially charged with murder, since April 2019 while undergoing numerous mental health assessments.
Justice Michael Copley will sentence Hill on the basis that he had intent to cause serious harm to Dr Dunne but had a substantial impaired ability to control himself and know he ought not do the act.
Dr Dunne's daughter Kate said the family had been suffering while in limbo for five years.
"How can we come to terms with his death when there is nothing but delay and disappointment."
Dr Dunne's sister Lisa McKay said the crime's ripple effects had been felt every day.
"This was not necessary. This was preventable. This was senseless," she told the court.
"This was an evil act."
Dr Dunne was remembered as a "pillar of support" by his daughters who said they felt robbed of sharing future memories like walking down the aisle or their children meeting their grandfather.
"I just really, really miss my dad," daughter Claire Dunne said.
Justice Copley is due to sentence Hill on August 27.
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