An 18-year-old man is due to appear in court charged with the murder of teenager Paul Erhahon.
Theo Diah, of Anglian Road, Leytonstone, will appear at Waltham Forest Magistrates' Court. He is also charged with the attempted murder and grievous bodily harm of a 15-year-old boy.
Unemployed Diah is the fifth person to be charged with the schoolboy's killing.
Paul, 14, died from a stab wound to the heart after he was attacked in the foyer of a block of flats in Leytonstone, east London on April 6.
A 10th teenager was arrested in east London connection with Paul's murder. The 13-year-old is currently being interviewed at a nearby police station.
Four other teenagers have been charged with the schoolboy's murder. The boys - aged 13, 14, 15 and 17 - are also accused of the attempted murder and grievous bodily harm of a 15-year-old boy.
They were remanded in custody at Waltham Forest Youth Court last week and will appear at the Old Bailey on April 24.
Detectives have also arrested a 19-year-old man and three boys, one aged 14 and two aged 15, who have been bailed until June while further inquiries are carried out.
Paul was the seventh Londoner under 16 to be murdered since the end of January.
He attended Kingsford Community School in Beckton, east London - the same school as 15-year-old Adam Regis, who was stabbed to death last month.
