"Advocates are undertaking a massive review of convictions in a North Carolina county where one prosecutor was disbarred for misconduct in the Duke University lacrosse case and another was suspended for ethics violations. Inspired by the innocence claims of Darryl Howard, who was freed Wednesday after spending 21 years in prison for two slayings he says he didn’t commit, the North Carolina Center on Actual Innocence has spent about two years quietly combing through hundreds of cases from Durham County of people who remain behind bars. The group has focused that investigation on about 20 cases, the center’s executive director, Chris Mumma, told The Associated Press on Thursday. She said four directly involved work by Mike Nifong, the prosecutor in the Duke case; more than half were handled by other staffers during his nearly three decades prosecuting crimes in Durham. Mumma would not say specifically why the center zeroed in on those 20 cases. However, cases in North Carolina and elsewhere have been re-examined when there are problems with evidence or witness testimony, or suggestions of misconduct by police or prosecutors. Re-examining the cases became necessary after the Duke case and after Howard’s conviction was thrown out, said defense attorney Kerry Sutton, who defended some of the three lacrosse players accused of rape by a stripper a decade ago.........A judge ruled Wednesday that DNA evidence showed Howard didn’t participate in the rape and murder of a woman and her 13-year-old daughter in 1991. Judge Orlando Hudson freed him from prison. Hudson two years ago also threw out Howard’s sentence, saying Nifong failed to share with defense attorneys a police memo and other evidence that pointed to suspects other than Howard. Howard remained jailed despite the 2014 ruling, and an appeals court decided Hudson had not heard enough evidence. Nifong did not return calls to his home seeking comment Wednesday or Thursday. His successor, Tracey Cline, was dismissed from office and suspended from practicing law for accusing Hudson of bias and violating rules by seeking prison records for two inmates. The Associated Press couldn’t find a working number for her, and an attorney didn’t return a message. Echols and Mumma agreed two years ago, about the time the judge first ordered Howard’s release, that they ought to investigate whether more cases of questionable prosecutorial conduct remained unearthed. Mumma and her staff began by searching for claims of innocence or constitutional violations in 1,120 cases in which the defendants remained imprisoned. They sent letters to 620 inmates asking for details about their cases, and based on the responses have begun a deep look into 20. Echols has promised to cooperate with investigating any questionable cases, saying Thursday that the perception of the justice system, and specifically of his office, “is almost as important as the reality of whether or not we are being fair or doing our jobs with integrity.” The review work is similar to that of the conviction integrity units now active inside about two dozen of the more than 2,300 local prosecutorial offices around the country.........Concern about whether prosecutors in the state’s fourth-largest city have failed to sort the guilty from the innocent has persisted without resolution since the Duke lacrosse case a decade ago, local attorneys said. If Nifong and Cline were aberrations while most prosecutions were by-the-book, “they were aberrations at the very top of the office, so I would be concerned with trickle-down,” said Theresa Newman, co-director of the Wrongful Convictions Clinic at the Duke University law school."