A 35-year-old man has been found not guilty of murdering an Irishman in Western Australia in December 2017.

Charles McCarthy, from Upper Aghada in Cork, died following an altercation in Perth when he was walking along Riverside Road in East Fremantle with his wife and a friend in the early hours of Saturday 23 December.

Mr McCarthy, 32, worked as a cable layer in Perth and had two children.

Andrew Doan was accused of using a screwdriver to attack Mr McCarthy, resulting in his death.

Mr Doan claimed that he acted in self-defence.

Mr Doan had been fishing in the Swan River when he got into an argument with Mr McCarthy, his wife Nicole and their friend Jason Curran.

The group had been walking towards a hotel after a Christmas party and they asked Mr Doan if he had caught anything while fishing. He told them he was not having much luck.

The court heard Mr Curran made a comment that "fisheries will come and get you", which Mr Doan thought was racist.

A row began and Mr Doan said he took a screwdriver, which he was using for crab fishing, from his pocket.

Mr Doan was accused of deliberately driving a screwdriver into Mr McCarthy’s left temple, inflicting a fatal brain injury.

However, he said Mr McCarthy's death was the result of a tragic "freak accident".

Mr Doan claimed that he acted in self-defence and that while defending himself from attacks by Mr McCarthy, the screwdriver accidentally pierced his skull when both men fell to the ground.

Mr McCarthy's wife, Nicole, had earlier told the court that she had no idea about the alleged comments made by Mr Curran.

She said Mr Doan chased the three following the alleged comments, threatening them.

Ms McCarthy said Mr Doan then allegedly retreated to a car park, where he was pursued by Mr Curran and Mr McCarthy.

Ms McCarthy denied that her husband had confronted Mr Doan after being provoked by Mr Curran.

She told the court that after both parties threatened to call the police, she saw her husband "just go down, his legs buckled under him".

Ms McCarthy said her husband had a visible puncture wound on his head. She said that she and Mr Curran administered first aid until police and paramedics arrived.

Emergency staff who attended the site all testified that Mr McCarthy showed no sign of life when they arrived before transporting him to Royal Perth Hospital. The court also heard that Mr Doan waited for authorities to arrive.

A red flathead screwdriver that belonged to Mr Doan was found by forensic scientists to be the weapon used.

Today, the jury deliberated for one hour before finding Mr Doan not guilty of murder and the lesser charge of manslaughter.

Following the verdict, Chief Justice Peter Quinlan told Mr Doan: "You will be united with your family shortly."

Mr Doan wept as the jury handed down the decision and his supporters also cried upon hearing the verdict.

He described the past 13-and-a-half months as "a crazy rollercoaster", thanking them for their support.

"It's really good to be back with everyone, family and friends. I've missed them all so much," he said.

Members of Mr McCarthy’s family were also on hand for the verdict.