A TEENAGER stabbed his grandmother to death in a frenzied knife attack as she lay naked in the bath.

Pietro Addis used two knives, stabbing Sue Addis 17 times on January 7 last year.

He phoned police who found her body slumped in the blood-stained water at her home in Brighton.

A court heard grandson Pietro had been staying with Mrs Addis following an argument with his step-mother and he was abusing illegal drugs and ADHD medicine.

Pietro Addis, now 19, was only 17 when he attacked his grandmother in the bath.

He denies murder.

Mrs Addis, who was 69 when she died, and her family ran the Donatello and Pinoccho Italian restaurants in Brighton, both popular with celebrities and footballers.

The much-loved restaurant owner was a well-known figure in the city.

Lewes Crown Court heard Pietro called police just before 7pm on January 7 last year.

The catering student, who also worked part time at the family restaurants, told the 999 operator: “I’m calling to hand myself in.

“There’s been a murder.”

When the operator asked how it happened, Pietro Addis said: “No comment”.

Asked how sure he was his grandmother was dead, he said: “100 per cent”.

Rossano Scamardella QC, prosecuting, told the jury police found three knives at the scene.

One was underneath Mrs Addis's body in the bath.

Another was found on the bathmat and a third was found inside a jacket belonging to Pietro Addis.

Mr Scamardella said: “The post-mortem examination revealed 17 stab wounds to the body.

“Two to the neck, four to the chest, five to the abdomen, four to the left arm and two to the left leg.

“One of the wounds to the chest, which cut through a rib, would have required a severe degree of force.”

Mrs Addis was attacked as she lay in the bath and did not put up a fight.

“There were no defensive injuries,” Mr Scamardella said.

“The bath was full of blood-stained water and there was soaked and torn newspaper floating in that water.

“Mrs Addis was slumped in the bath having been stabbed to death.”

The court heard Pietro’s parents split up not long after his birth and his mother died when he was six years old.

In the summer of 2019, Pietro began smoking cannabis.

“It seems that Pietro was selling clothes to fund his cannabis habit,” Mr Scamardella said.

“He was using Xanax and cannabis and he would use a high dose of Adderall which was ADHD medication.

“In late December, with Pietro’s behaviour become more worrying, matters came to a head, when shortly after Christmas he was asked to leave his father’s home and live with his grandmother, Susan Addis, and within a little over a week he had killed her.

“His case is that he was suffering from paranoid psychosis at the time, diminishing his responsibility for the killing and he has pleaded guilty to manslaughter to reflect that.

“However, it is the Crown’s case that Pietro suffered no such psychosis at the time of the killing, and he bears complete responsibility for the murder of his grandmother,” Mr Scamardella said.

“In the time since he killed his grandmother, Pietro Addis has been prescribed no anti-psychotic medication.

“The prosecution will contend that if he had suffered a psychotic episode of the type that led to him killing his grandmother in the frenzied way which he did, it is inconceivable that the psychosis would resolve without medication of some description.

“As tragic and as bewildering as it may be, Pietro Addis murdered his grandmother,” Mr Scamardella said.

Pietro Addis denies murdering Sue Addis at her home in Cedar Gardens, Brighton.

The trial continues.