The father of schoolboy Damilola Taylor is confident four years after his son's murder that the killer will be caught.
Police say they are confident they will catch Damilola's killers
Ten-year-old Damilola was fatally stabbed on his way home from school in Peckham, in November 2000.
Richard Taylor told BBC News: "I still believe the police are not resting until justice is obtained for those who murdered our son."
The Damilola Taylor Trust and police are holding a "youth summit" to warn of the dangers of carrying knives.
"We have been assured by the outgoing commissioner of police John Stevens that this will not be a wasted effort," Mr Taylor said.
Four youths were cleared of Damilola's murder at the Old Bailey in April 2002.
At the trial evidence from the prosecution's key witness, a 12-year-old girl, was thrown out by the judge who ruled it was unreliable.
Mr Taylor said he had faith in the judicial system and the police.
"We are hopeful the investigation is still on and that one day someone will be brought to justice".
"We want justice done. Some one killed him and that person has to be locked up."
Mr Taylor said he still found the loss of his son "difficult to cope with".
Police said in October they had searched several Peckham homes the previous month.
At the time Scotland Yard said it was confident the case would be solved.
Mr Taylor said he hopes to pass on positive lessons learned from his son's death to young people in London and to raise awareness among children of the danger of carrying weapons.
However, he urged parents to take a stronger role in looking after their children.
"From leaving home in the morning to when he comes back in the evening because what the child does outside - [parents are] oblivious to it," he said.
Dean of Southwark Colin Slee said police had done a lot of work in the Peckham to improve safety.
"I think children feel safe when they are in school, both primary and secondary, but it's when they are on the streets that there's a difficulty."
He too was confident the killer would be caught as the "gap" between police and the community was changing for the better.
"I think ultimately the killers will be found."
He said the role of parents was the most important aspect.
"All of the head teachers that I speak to say that they are fairly content with the security of the children in school and not content with the way parents are behaving."
He said children "are kicked out in the morning and told to go to school by themselves in street that are quite dark", children frequently return home to empty houses, or wander the streets, often in groups "purely because they are bored".