Grandson who stabbed his grandmother 17 times found not guilty of murder

  • WATCH: ITV Meridian's Andy Dickenson explains more about the case

A teenager charged with murdering his grandmother in Brighton has been found not guilty.

Pietro Addis was acquitted by a jury at Lewes Crown Court on Friday, (3 March) of the murder of Sue Addis, who was found dead at her home in Cedars Garden on January 7, 2021.

Addis, who was 17 at the time, pleaded not guilty due to his responsibility being diminished as a result of paranoid psychosis.

Pietro Addis, now 19, was arrested after he rang 999 and told the police operator: "There’s been a murder."

Police body-worn camera footage of his arrest was shown at his trial at Lewes Crown Court.

Officers found three knives at the property, one with a serrated edge. At least two were used to stab Mrs Addis 17 times.

In the video, Pietro Addis, can be seen staring blankly ahead while answering questions from police as they detained him in the house at Cedar Gardens.

  • WATCH: Police bodycam footage of the arrest

The Addis family own Italian family restaurants in Brighton popular with celebrities and footballers.

Pietro moved in with his grandmother after an argument with his father and step-mother after Christmas in 2020. Little over a week later, he had killed her.

Writer and broadcaster Simon Fanshawe knew Mrs Addis and the family well.

She was known for supporting several local charities and hosting parties, including Mr Fanshaw's wedding.

"She was incredibly skillful, as well as being extraordinarily nice," he said.

  • WATCH: Simon Fanshawe said he knew Mrs Addis and the family well

Pietro Addis admitted the manslaughter of Sue Addis by diminished responsibility. He denied murdering her, saying he was suffering from a paranoid psychosis at the time.

Dr Peter Misch described Pietro Addis as "emotionally disturbed".

He believed his grandmother wanted to kill him, a psychiatrist said.

Asked what he thought of Pietro Addis when he interviewed him at a secure hospital, Dr Misch said: "I’d formed the opinion he was psychotic and it was relatively brief and transient.

"It only lasted a period of time and it resolved without medical, drug intervention."

Sue Addis had told friends she was concerned about her grandson’s mental health and drug use in the months before she was killed.

Sue Addis was a restaurant owner and well-known supporter of several charities in Brighton.

The jury at Lewes Crown Court heard Addis suffered paranoid psychosis at the time of the killing.

Toxicology tests found Pietro Addis had MDMA, Cannabis and Ketamine in his system.

Dr Misch said: "They were part of the bigger picture of his mental disturbance. I can’t say the drugs didn’t have an effect."

However, Dr Duncan Harding, who assessed Pietro Addis before he was discharged from hospital, described the teen as an unreliable malingerer.

A melting pot of factors including feelings of entitlement and anger led to the brutal killing, the child and adolescent psychiatrist said.

The teenager was inconsistent, relaxed and calm when talking about a delusional belief his grandmother wanted to kill him, Dr Harding said.

After the arrest, police found a knife under Mrs Addis, another larger knife nearby and a third knife in a jacket belonging to Pietro Addis.

Four of her 17 wounds would have been fatal on their own, the court was told.

The teenager told Dr Misch he had not planned to kill his grandmother, and did not have an explanation, but things had "built up" after Christmas.

Detective Superintendent Mark Chapman, of the Surrey and Sussex Major Crime Team, said: "This is a tragic case in which a much-loved grandmother, who was widely respected in the Brighton and Hove community, has lost her life in the most terrible circumstances.

"Our thoughts remain with the Addis family and loved ones who have behaved with dignity and compassion throughout this harrowing ordeal."

Addis will be sentenced on May 5.