Detectives investigating the murder of 15-year-old Sofyen Belamouadden at one of London's busiest Underground stations have arrested a teenage girl.
Metropolitan Police investigators held the girl suspect and three more teenage boys during a series of raids in south London.
The move brings the total number of people arrested over the attack at Victoria during last Thursday's rush-hour to 24.
Witnesses said several young girls looked on as Sofyen was chased into the busy Tube station and hacked to death with knives.
Twelve teenagers have been charged with killing the aspiring footballer from Acton, west London. Three of the teenagers, all aged 17, have appeared before West London Youth Court. The male youths spoke only to confirm their names and addresses during the short hearing. The remaining nine teenagers are also due to appear before the court.
Sofyen suffered multiple stab wounds to his chest when he was set on by a mob of teenagers at Victoria Tube station.
The attack began on steps leading into the station in Terminus Place and ended in a booking hall for the Circle and District Tube lines. It took place at about 5.20pm as the evening rush hour of train, Tube and bus commuters got into full swing.
Sofyen, a pupil at the Henry Compton School in Fulham, west London, was taken to a central London hospital but was pronounced dead at 6.15pm.
The teenager played football for Acton Garden Village Youth Sunday League team in west London and for Chelsea Kicks, a scheme run by the Premier League club for young people in deprived areas. A spokesman for the club described him as a "talented footballer" and a "valued participant" on the scheme.
Police charged 12 youths - four aged 16 and eight aged 17 - with Sofyen's murder. Two 15-year-olds, four 16-year-olds and a 17-year-old have been released on bail and a man in his thirties will face no further action.
