The judge in the Stephen Lawrence murder trial has urged police not to "close the file" on catching the rest of his killers.
Mr Justice Treacy made his appeal as Metropolitan Police Commissioner Bernard Hogan-Howe said that the remaining culprits "should not rest easily in their beds". It is understood that police plan to meet next week to assess where the case stands.
Gary Dobson, 36, and David Norris, 35, received life sentences at the Old Bailey on Wednesday for the racist murder of Mr Lawrence nearly 19 years ago. The court has heard that a gang of five or six white youths set upon the A-level student in Eltham, south east London, in 1993.
Dobson, who is already serving a five-year sentence for drug-dealing, was sentenced to at least 15 years and two months. Norris was given a minimum of 14 years and three months for the murder, which the judge said was a "terrible and evil crime".
Mr Lawrence's father Neville told reporters outside court that he hoped the pair would "give up the rest of the people" involved. His mother Doreen said the sentences were "quite low", but she appreciated the judge's hands were tied and she would now "start moving on".
In court, Mr Justice Treacy called forward Detective Chief Inspector Clive Driscoll, who has been the senior officer in the case for a number of years. He told him that the public inquiry into the circumstances surrounding Mr Lawrence's death had "shamed and humbled" the Met, but praised the hard work done in recent years.
The judge went on: "At least a measure of justice has been achieved at last. However, the convictions of Gary Dobson and David Norris will not, I hope, close the file on this murder. On the evidence before the court, there are still three or four other killers of Stephen Lawrence at large.
"Just as advances in science have brought two people to justice, I hope the Metropolitan Police will be alert to future lines of inquiry, not only based on developments in science but perhaps also information from those who have been silent so far, wherever they may be."
Later, a spokesman for the Met said police were looking into information they have received in the past 24 hours. He said: "We can confirm that we have received a number of telephone calls in light of the verdicts and today's sentencing. This information will be evaluated."
Mr Driscoll told BBC News that officers would be visiting Dobson and Norris in prison to see whether they would be willing to assist the inquiry and said he remained "optimistic" about further progress being made in the case.