Prosecutors have dropped rape charges against three former students of a top US university in a case which sparked national debate.
Mr Nifong dropped the rape charge but two others still stand
The three white students from Duke University were accused of attacking a black woman who worked as a stripper.
The men were all members of Duke's lacrosse team and the attack was said to have taken place at a team party.
They still face charges of kidnapping and sexual assault. They have always denied the charges.
District Attorney Mike Nifong dismissed the rape charges because the woman was not sure about a key detail of the alleged attack.
The woman could not be sure that a penis was the body part that penetrated her vagina, he wrote in court papers.
The woman says the three men attacked her in a bathroom at an off-campus party in March 2006 at which she had been hired to perform as a stripper.
The defence accuse the woman of giving different versions of her story.
The case triggered a major investigation at the North Carolina university, which cancelled the rest of the lacrosse team's season.
It also sparked a debate about racial and social tensions in the town.