A fifth teenager has been charged with the murder of Shakilus Townsend who was stabbed to death in south London last week, police said on Friday.
Detectives said the 16-year-old boy was due to appear before Sutton Magistrates Court later.
Townsend, 16, was found with a stab wound in the entrance to a block of flats in Thornton Heath last Thursday. He died in hospital the same night.
On Thursday four teenagers, including one girl, appeared in court charged with his murder. Tyrell Ellis, 18, two other young men aged 16 and 17, and a 15-year-old girl were remanded in custody.
A 22-year-old man has been released on police bail until a date in August pending further investigations.
Townsend was one of 19 teenagers to die violently in the capital this year.
The Metropolitan Police have said knife crime was now the force's top issue.
Officers say they have searched 27,000 people, arrested more than 1,200 and seized 500 knives in London during a six-week crackdown. A 75-strong team has also been set up to target those carrying weapons.
"This reflects that tackling knife crime is the number one priority for the Met at this time," said Deputy Commissioner Paul Stephenson.
