A martial arts expert has been jailed after he fatally kicked a 70-year-old man in a road rage incident while his family watched in horror.
Francois Joseph Ghassibe was on Monday sentenced for the manslaughter of Brian Maxwell Richardson after he was previously found not guilty of the more serious charge of murder.
Ghassibe, 32, was in the back of a taxi on West Terrace in Adelaide when his driver was cut off by 70-year-old Brian Richardson on April 1, 2022.
When Ghassibe tried to break up a confrontation between the taxi driver and Richardson, who had left their cars in the middle of traffic, Richardson started pushing and punching him.
Ghassibe, who was 40 years Mr Richardson's junior at the time and 10 centimetres taller, retaliated with devastating effect.
As Richardson's wife, brother and sister-in-law watched on from their car, Ghassibe - who later told police he had a background in martial arts - launched several blows at the older man before delivering a final, terminal kick to the chin, causing him to fall backwards and hit his head on the bitumen.
A post-mortem examination found the impact of his head hitting the roadway to be the killing blow.
Ghassibe climbed back into the taxi and left while bystanders rushed to Richardson's aid.
He was later pronounced dead by paramedics.
Ghassibe pleaded guilty to manslaughter but denied that he murdered Richardson.
SA Supreme Court Justice David Peek found Ghassibe's kick was unlawful as it was not in genuine self-defence and was a dangerous act he should have realised risked seriously injuring or killing Richardson.
However, he was not satisfied that his actions demonstrated a murderous intent.
A psychological report found Ghassibe had a troubled upbringing and was frequently subjected to physical assaults and racial abuse on account of his Lebanese and Mauritian heritage.
He suffered from post-traumatic stress disorder, which was exacerbated when his wife was severely assaulted by a "large, psychotic man", forensic psychologist Richard Balfour found.
Ghassibe's hyper-vigilance and hyper-arousal contributed to his state of panic during Richardson's "unprovoked attack", lowering his moral culpability, Peek found.
The cocaine and alcohol circulating through his bloodstream and the temporary loss of vision in his only good eye from being punched and spat at also impeded his ability to act rationally and proportionately to the situation.
Despite showing little contrition at the time, Ghassibe had shown remorse for his actions during the case and was on the road towards rehabilitation, the judge said.
Nevertheless, Peek said he was deserving of "substantial punishment" for the irreparable loss suffered by his victim's family and friends.
Richardson's son Shane said his memories are "beyond painful" in a statement read out to the court.
"I've lost my dad, my best mate," he said.
"No more laughs, no more fishing together, no more fixing shit, no more brainstorming, no more anything. It's final and I'll never see him again.
"I can only hope there is justice for dad."
Peek sentenced Ghassibe to six years and nine months in prison.
His non-parole period was set at four years and six months, backdated to his arrest.
Ghassibe blew a kiss to his parents in the public gallery as he was ushered out of court.
His lawyer Nick Vadasz told reporters outside his client was "very remorseful" and lamented that his initial guilty plea for manslaughter was not accepted, which would have saved all involved from a lengthy trial.
Ghassibe will be eligible for parole in October 2026.
