DECATUR, Ga. — A man wrongly convicted of rape, kidnapping and robbery was freed yesterday after 17 years in prison — exonerated by a new test of DNA evidence and “unusually” helpful prosecutors.Clarence Harrison, sentenced to life in prison in 1987 on charges of sexually assaulting a hospital worker, walked out of a courthouse in DeKalb County surrounded by ecstatic friends and family.”I think I had given up years ago,” the 44-year-old Harrison said. “I think God just carried me on through it.”The Georgia Innocence Project, which represented Harrison, said it usually runs into road blocks when working with prosecutors. “Many have not been terribly cooperative,” group director Aimee Maxwell conceded.DeKalb prosecutors, however, were “unusually” helpful with Harrison’s case, she said.After Harrison asked the group for help last year, the district attorney’s office found evidence stashed in an old box and sent it to a lab for DNA testing. The new test confirmed Harrison was not guilty of the 1986 attack.”There’s nothing I can do to give Mr. Harrison back 17 years of his life, but I can say the system worked — once we obtained the evidence,” said Jeffrey Brickman, the DeKalb County district attorney.A motion for a new trial was filed on Harrison’s behalf, and prosecutors transferred Harrison to a local jail so he could walk out of the courthouse a free man.Judge Cynthia Becker granted the new trial request yesterday and then dismissed the charges. The courtroom erupted into applause and tears.Harrison wouldn’t say whether he would seek compensation for his time in prison, but he said he wasn’t bitter. Friends said Harrison wants to focus on finding a job and getting married before considering his next legal step.The original case against Harrison hinged on the victim’s testimony and evidence of seminal fluid. However, crime labs testing the physical evidence at the time could only narrow the field to 88 percent of all men.After Harrison’s lawyers appealed, a private lab determined evidence was unsuitable for further DNA analysis.According to a police report, the 25-year-old victim, who worked at Grady Memorial Hospital, was standing at a bus stop when a man walked up, struck her in the face and said, “If you scream, I’ll kill you right here.” He walked her to a wooded area and repeatedly raped and sodomized her, the report said.The attacker took her money and watch and knocked out two front teeth.The woman initially identified Harrison from a photographic lineup and later identified him at the trial.The Georgia Innocence Project, founded two years ago, helped lobby the Legislature to approve a 2003 bill that allows those wrongly convicted of violent crimes to prove their innocence through DNA testing. Harrison’s case is the first to successfully use the new state law.”It’s easy to call this our first major victory,” Maxwell said. “We’ve walked out of court with our client.”