A teenager who stabbed to death his sister’s ‘secret’ boyfriend from Wembley has been found guilty of manslaughter.

The 17-year-old, who was 16 at the time of the incident and cannot be named for legal reasons, fatally stabbed Risaan Udayakumar on July 10.

The 18-year-old civil engineering student, who lived with his parents, died in hospital after being stabbed in the chest at his girlfriend’s detached home in Watford.

Shortly before 10pm on July 10, a member of the public called police after he discovered Risaan crouched in the corner of the property’s adjoining garage with multiple stab wounds, following a disturbance.

In the wake of his death, Risaan’s distraught family said: “Our family is devastated and will never be the same again. Risaan leaves a gap that cannot be filled and we do not understand why this has happened to such a bright and caring young man.

“Risaan was very family orientated and did not believe in violence.”

During the trial at St Albans Crown Court, the jury heard heard the parents of the boy and his 19-year-old sister were away on holiday at the time of the killing and had given strict instructions that the siblings were not to have friends over to the house.

Because of the parents’ “strict views” about relationships, their daughter had decided not to tell them that she was in a relationship with Risaan.

On July 10 she picked him up from Watford station and returned to her home.

She hid him in the garage when she heard her brother banging on the door shouting “Where is he?”

Michael Speak, prosecuting, said: “Having searched the bedroom and bathroom and having failed to find Risaan, the defendant went into the garage and there he found Risaan, who was down in a corner at the front of the garage.”

Risaan offered no resistance and only raised his arms to shield his face, the prosecutor added. When she saw blood, his girlfriend realised he had been stabbed.

The jury returned a verdict of manslaughter due to loss of self-control on Wednesday.

Det Insp Justine Jenkins said: “This has been an extremely difficult and emotional time for Risaan’s family and my thoughts remain with them. They have shown great dignity throughout as they continue to try and come to terms with what has happened. This is a tragic case which has affected many lives.”

The teenager will be sentenced in February.