A week after teenager Ashley Hedger was stabbed to death in east London, police are warning that his killer is "still out there".
Ashley died two hours after he was stabbed
The 16-year-old died on 16 January, two hours after he was stabbed in Plashet Road, Upton Park.
He was chased after two members of a group he was with allegedly tried to rob two other youths.
Earlier in the week detectives said they were questioning seven men over the murder. They have all now been released on bail.
Detective Superintendent Sue Hill, from the Specialist Crime Directorate at Scotland Yard, said: "We have made arrests but we have not charged anyone with murder - the murderer is still out there.
"Ashley was a really nice boy who was in the wrong place at the wrong time.
"This was a spontaneous vicious attack and the person who killed Ashley is clearly very dangerous and capable of doing something like this again. It was a ferocious attack in broad daylight outside a shop."
She appealed for witnesses to come forward.
"Five or six youths were involved in chasing Ashley but not in the stabbing and we know that.
"I want those youths to come forward and help us, it will be much better if they do that than us having to hunt for them."