The judge who presided over the Sue Addis trial has described the case as “deeply sad and distressing” after her teenage grandson was acquitted of murder.

Pietro Addis, 19, was found not guilty of murder after stabbing Mrs Addis at her home in Cedars Gardens in Brighton in January, 2021.

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

He has admitted killing Mrs Addis, 69, however, and will be sentenced in May for manslaughter.

Speaking after the jury delivered a unanimous verdict, Judge Christine Laing KC told the jury at Lewes Crown Court that “this was a deeply sad and distressing case without a shadow of a doubt”.

Judge Laing said Addis would be remanded in custody ahead of sentencing with a new report by an independent psychiatrist being prepared.

During the trial, Dr Peter Misch told the court that Addis had suffered from the delusional belief that his grandmother was going to kill him.

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During an interview in custody, the teenager is reported to have said: “I thought she was going to kill me.”

The psychiatrist, instructed by the defence, told the court that Addis had suffered from a “brief, transient paranoid psychosis” during the killing.

Addis was found not guilty due to having diminished responsibility at the time of the killing. The jury forewoman said he was found guilty of manslaughter.

This means that the defendant did not have the ability to understand the nature of their conduct, form a rational judgment and/or exercise self-control was substantially impaired.

Dr Misch said: “Pietro’s abnormal mental function, including the belief that his grandmother would harm him, impaired his ability to form a rational judgement and impaired his self-control.”

This is the third time that the case was tried after previous attempts were cut short for “a variety of reasons”.

Mrs Addis was a popular Brighton restaurateur who ran Donatello in The Lanes and Pinocchio in New Road.

She was described as a "warm and generous person" who always believed her grandson would "turn things around".

Addis will be sentenced on May 5.