A teenager brutally murdered an acquaintance with a kitchen knife after declaring rap music made him "want to stab somebody," a court heard today.
The 16-year-old, who cannot be named for legal reasons, launched an unprovoked attack on Fico Dougan, 17, in front of a two-year girl at a house in Ockley Road, Broad Green.
Fico, of Thornton Heath, died of a stab wound to the heart soon after the attack on September 25 last year.
At the opening of the accused teen's trial for murder today, the Old Bailey heard the fatal stab wound was inflicted with such force that it entered through Fico's chest, passed through a chest bone and emerged from his back.
Prosecutor Martin Hicks told the court Fico and the 16-year-old knew each other but "there was no known hostility".
Each had been visiting the house in Ockley Road on the afternoon of the killing.
The defendant, a 19-year-old girl, Fico and Montana Riley, Fico's girlfriend, were watching TV in the living room with the girl's two-year-old sister.
Mr Hicks said: "The defendant was listening to music on his headphones. He was heard to say words to the effect of, 'When I listen to rap music I want to stab somebody.'"
Later, the defendant rose from his seat and walking to the kitchen with what Miss Riley described as "a vague stare".
The court heard he returned to the room with a kitchen knife and repeatedly stabbed Fico, while Miss Riley desperately tried to stop him, before leaving the house.
He was arrested by police at his home in Mitcham, where officers allegedly found him burning clothes in his back garden.
The defendant denies murder.
His defence lawyer, David Nathan, will argue for a lesser conviction of manslaughter on the grounds of diminished responsibility due to post-traumatic stress disorder.
The trial continues.