Four quizzed over schoolboy's death
Police are questioning four suspects after a schoolboy was killed while "selflessly protecting" his younger brother.
Detectives are hunting up to nine gang members following the death of 15-year-old Negus McClean.
Four males, aged 14, 16, 18 and 20, have been arrested over his death, while relatives have paid tearful tributes to the aspiring musician.
Family members hit out at the "disgusting act of violence", but vowed to pray for Negus's killers.
His cousin, Noel, called for an end to knife crime. Fighting back tears after laying flowers at the scene of the attack in Edmonton, north London, the 25-year-old described Negus as "intelligent, mature and selfless".
"He was dying protecting his brother," he said. "It was a selfless act. He paid with his life."
Speaking at the scene, Detective Chief Inspector Stephen Clayman said Negus died after being chased by "seven, eight or nine" youths riding bikes.
Relatives and a host of school friends arrived to lay flowers as teachers and friends of the teenager came forward to pay tribute to him.
Noel, who declined to give his surname, said: "It was just a disgusting act of violence. I pray that a change happens, I pray for the guy that did this to my cousin."
Negus was preparing to celebrate his 16th birthday in two weeks' time and was hoping to embark on a career as a rapper after leaving school, relatives said.