Guilty Verdicts in 1993 Racial Murder Case That Changed Justice in Britain LONDON - More than 18 years late by the reckoning of the victim's family and many others across Britain, a jury at the Old Bailey on Tuesday found two white men guilty of the racially motivated stabbing and murder of a black youth named Stephen Lawrence on a south London street in April 1993. The convictions were the first in the case, and they seemed likely to lead to lengthy jail terms for the two men, who were juveniles at the time of the attack, when the court sits again on Wednesday. For Britain, the convictions were a defining moment. Over the years, the Lawrence case had become as famous an emblem of justice denied or perverted as the Dreyfus case in France in the 1890s. It stood out because it occurred in a country where a vast majority of the 500 to 700 murders each year are successfully prosecuted, and because it involved five or six white youths in an unprovoked attack on an 18-year-old black student on his way home from a youth club. In a 1999 report, a judge-led inquiry struck one of the harshest blows in the history of Britain's most famous police force, accusing Scotland Yard of "pernicious and persistent institutionalized racism" in its handling of the case and in other matters involving Britain's nonwhite population. Police failures in the Lawrence case were compounded by the defiant attitude of the white gang involved. Suspects in the case repeatedly mocked the years of inconclusive investigation; the pursuit of the case by Mr. Lawrence's parents, who were born in Jamaica; and the abortive private prosecution they brought against five members of the gang in 1994 when the police failed to lay a case of their own. What ultimately turned the tide was a change in the criminal law in 2005, one of many reforms that grew out of the case and out of a wave of public support for the victim's parents, Neville and Doreen Lawrence. A new awareness of racial sensitivity in police and prosecutorial procedures, and of the alienation that Britain's ethnic minorities feel in regard to the police, both have their roots at least in part in the anguish of the Lawrence case, British commentators say. The change in the law partly laid aside the centuries-old "double jeopardy" prohibition against a second trial for the same offense after a person has been acquitted in a first trial. The law now allows retrial of murder cases if new evidence becomes available. In the Lawrence case, it was microscopic traces of clothing fiber, hair and blood found on the clothing of Mr. Lawrence and the two men convicted on Tuesday, made possible by advances in laboratory techniques. Prosecutors said the traces proved that the two men - Gary Dobson, now 36, and David Norris, 35 - were present at the murder. Both men maintained that they were elsewhere and that the forensic evidence was contaminated by police mishandling. Mr. Dobson was acquitted of murder in the case when the private prosecution brought by the Lawrences in 1994 collapsed because of a judge's ruling that the testimony against him and two other defendants by witnesses was unreliable. The charges against Mr. Norris in that case were dropped before trial. Mr. Dobson was unrepentant on Tuesday, turning to the jury and saying, "You have condemned an innocent man - I hope you can live with yourselves." Mr. Norris raised a fist to members of his family and other supporters in the courtroom. Later, though, Mr. Dobson's lawyer made an appeal to the judge that suggested Mr. Dobson might abandon his denial of any involvement in the murder. The lawyer told the judge that Mr. Dobson, who was 17 at the time, "wasn't the prime motivator in the attack, he wasn't their leader" when Mr. Lawrence and a friend were attacked as they waited for a bus at twilight in a predominantly white area 10 miles from central London. The jury was told only after the guilty verdicts that Mr. Dobson was currently serving a five-year prison term imposed in 2010 for drug offenses, and that Mr. Norris, who was 16 when Mr. Lawrence was killed, was convicted and jailed for a racially motivated attack on a black police officer in 2002. The police and prosecutors are now hoping that the two convicted men will try to win reduced sentences by providing evidence that could open the way for others to be charged. Senior police officers involved in the case vowed on Tuesday to keep investigating. They offered apologies to Mr. Lawrence's parents for police failings immediately after the killing, including the failure for two weeks to arrest or question suspects who were named by more than two dozen witnesses or to seize items of clothing - a jacket, a cardigan and two pairs of jeans - that ultimately yielded the microscopic evidence, after a new examination by a private laboratory in 2007, on which Tuesday's verdicts depended. Cressida Dick, an assistant deputy commissioner at Scotland Yard, offered a tribute to the Lawrences that many in Britain, dismayed by the years of official bungling, would have endorsed. "We pay tribute to Mr. and Mrs. Lawrence for the courage and dignity" they showed through the years it took to achieve convictions in the case, she said. They have contributed to major changes in policing, the law and indeed in society as a whole. But Mrs. Lawrence, a 59-year-old former teacher who has run a trust for underprivileged urban youths in her son's name, said, "The verdict today is not a cause for celebration." "How can I celebrate when my son lies buried - when I can't see him, or speak to him, and can't see him grow up, get married, have children or go to university?" she said. She added that she was relieved that "two of my son's killers have finally been caught," but "mixed with that relief is anger that me and my family were put through years of grief, and that we continue not to know if or when we will ever get full justice." Harvey Morris contributed reporting.