Four more people have been arrested in connection with the fatal stabbing of schoolboy Adam Regis.
Adam was stabbed to death in Beckton
Adam, 15, from Plaistow, was stabbed to death in Beckton, east London, on Saturday evening.
The four, aged in their late teens and early 20s, were arrested on Wednesday afternoon in east London.
Three people arrested on Tuesday have been released without charge and a 17-year old held on Monday has been released on police bail.
Of the four arrested, three were held in a car stopped by police in Upton Park, and the fourth was detained at an address in Forest Gate.
Adam, who was the nephew of Olympic sprinter John Regis, suffered a wound to the chest and abdomen when he was attacked at the junction of Boundary Road and Kingsland Road in Plaistow.
A Scotland Yard spokesman said: "We stress that the investigation continues and that all our points of appeal remain. All lines of inquiry do remain open."
Adam is thought to have been attacked as he made his way home from the Showcase Cinema in Beckton, sometime after 2100 GMT.