Detectives hunting the killer of 10-year-old Damilola Taylor are expected to charge three people today in connection with his death.
All three suspects were arrested four years ago but never charged. Their re-arrest is understood to follow a forensic breakthrough by detectives who have re-examined every piece of evidence from the original case using new DNA techniques.
The three suspects were among a group of more than a dozen local youths held by police in the months after Damilola was stabbed to death with a jagged bottle on a run-down estate in Peckham, south London, in November 2000.
Four other other teenagers, including two brothers, were charged with the murder and eventually stood trial at the Old Bailey in 2002.
They were acquitted after the evidence of a 14-year-old girl, who claimed she saw the killing, was thrown out of court after it was ruled unreliable.
It was claimed the girl had only said she had witnessed the murder because of a £50,000 reward offered by a newspaper.
Damilola's parents, Richard and Gloria, were told about yesterday's arrests in advance.
They had been planned for some time and were described as "highly significant". A police source said: "These are certainly not speculative arrests."
The three suspects were taken to separate police stations in London for questioning.
Detectives working on the case, now headed by Detective Chief Inspector Nick Ephgrave, will have until tomorrow to charge the three, or seek more time for questioning.
Their investigation has included raids at addresses close to the murder scene last October. They have also concentrated on finding new witnesses and breaking down the wall of silence that the original inquiry team met in Peckham.
Deputy Assistant Commissioner Bill Griffiths of Scotland Yard's Specialist Crime Directorate said: "These significant developments are the result of a determined effort to establish the truth of what happened on that day.
"I pay tribute to Mr and Mrs Taylor for their patience, understanding and support throughout the course of this investigation."
Damilola, who was born in Nigeria, was on his way home from a library in the late afternoon when he was attacked in what police believe was an attempted robbery. He was stabbed in the thigh and then bled to death in a nearby stairwell. His family had come to Britain from Nigeria only a few months earlier, seeking medical care for Damilola's sister.
Yesterday's arrests came after the outgoing Scotland Yard Commissioner Sir John Stevens said that the failure to catch Damilola's killers was his biggest regret and vowed that the hunt would continue.
The trial of the four youths originally charged - who were aged between between 15 and 17 by the time they were acquitted - ended in a shambles more than two years ago. Two were acquitted on the directions of the judge and the two brothers were cleared by a jury at the end of a three-month trial which, together with the police investigation, was estimated to have cost £10m. Mr Taylor, who sat through the whole trial, has refused to give up hope that the police would get it right.
Speaking on the fourth anniversary of Damilola's death last November he said: "We still believe in the judicial system of this country.
"I actually believe that the police will not rest until justice is obtained for those who murdered my son. We are hopeful that the investigation is still on and one day someone will be brought to justice. It has been very difficult. We find it difficult to cope. We still remember him every day, every night."
Sir John said: "I think what people need to understand is that we in the police never give up and these inquiries are never closed."
Mr Taylor praised the police investigation last night. He said: "The family are very encouraged with the news of today's arrests and the extent of the police investigation. All that we have ever wanted is justice for our son. The family have been kept fully informed by the police and we are pleased with the way things are going."