A man has been sentenced to a minimum of 22 years in prison for the “unprovoked” murder of a 15-year-old boy.

Imran Boudjellel, 20, was found guilty of the murder of Joseph Marafini, whom he fatally stabbed outside a branch of Sainsbury’s in October 2020, the Metropolitan Police said.

He was sentenced to a further six years, to be served at the same time, for grievous bodily harm for the stabbing of another 15-year-old in the same incident.

Kingston Crown Court heard that Boudjellel was part of a group of five young men who confronted Joseph and two of his friends outside the supermarket in Garratt Lane, Wandsworth, south London, on October 29 last year.

Boudjellel stabbed Joseph in the shoulder and in the neck, as well as stabbing the other teenager in the chest and arm, according to the Met.

The attack was captured on CCTV and also on the body-worn camera of an officer in a police van who happened to be passing.

The officers in the van were said to have immediately run to the scene and given first aid to Joseph. He was taken to hospital, but died shortly after.

Boudjellel was chased by officers into a nearby graveyard, where he was arrested.

The jury heard that a witness told police they had seen Boudjellel throw something over a wall, and a large knife and sheath were found in a car park nearby. The knife had blood on it that was matched to Joseph’s DNA.

Boudjellel’s DNA was also located on the sheath of the knife, according to police.

CCTV showed that Boudjellel had been the one who had used the knife to stab Joseph twice before running away from the scene with the knife in his hand, according to a Met Police report of the trial.

In a victim impact statement, Joseph’s aunt, Sara Marafini, told the court how Joseph was a loved and precious boy and that his mother, Natalie, had been left “a hollow person” by his killing.

Addressing Boudjellel, she said: “You knew nothing about him but in a second you took everything.

“Joseph did not say or do anything to you. He was still astride his bike, hands on the handlebars, when you lunged at him with your knife and he was stepping away from you (with his) arms in a defensive position when you punched that knife into his neck.

“You have damaged so many lives.

“Our family has changed for ever. Things will never be the same. We will always be missing Joseph.”

Detective Chief Inspector Vicky Tunstall, the lead investigator in the case, said: “I know this incident caused a great deal of public concern as it happened outside a supermarket at a busy time of the day with people going about their lives in an ordinary way. Nobody should expect to witness such an incident.

“This was a completely unprovoked attack by a man who was a habitual knife carrier and it is sadly another example of the senseless violence that has resulted in the death of a 15-year-old boy who was a beloved son and brother. His family have been left devastated by their loss and we continue to support them through this ordeal.”

She added: “I would like to praise the police officers who, despite being very young in service, were first on scene, chased and detained the suspect and provided CPR to try and save Joseph’s life.

“It is important for public safety that Imran Boudjellel has now been brought to justice and will no longer be able to inflict violence to anyone else on the streets of London for a considerable time.”