DURHAM, N.C. - A prosecutor’s decision to drop rape charges but keep other counts against three Duke University lacrosse players has left many legal experts — including some who had supported him — wondering what case he could have left.

Sexual offense and kidnapping charges remain against the defendants, but even some former backers of District Attorney Mike Nifong say the accuser may have lost her credibility for good after backing off a key allegation.

“I don’t understand why all the charges aren’t being dropped at this time,” said Norm Early, a former Denver prosecutor who works with the National District Attorneys Association and had previously approved of Nifong’s handling of the case. “It’s such an incredible credibility problem that you wonder how the prosecution could rehabilitate her on the other charges.”

The woman says Reade Seligmann, Collin Finnerty and David Evans attacked her March 13 at a team party where she had been hired as a stripper. In a five-page statement she gave police in early April, she wrote that she was raped vaginally, anally and orally.

Nifong dropped rape charges against the three men Friday, writing in court papers the accuser is no longer certain vaginal intercourse had occurred. That is required for a rape charge under state law, and “the state is unable to meet its burden of proof with respect to this offense,” Nifong said in the filing.

“He got a rape indictment, so presumably he must have felt there was unequivocal evidence there was penetration,” said Duke law professor James Coleman, a frequent critic of Nifong’s handling of the case. “And for him now to say the only person who could have established that now isn’t sure, that’s pretty extraordinary.”

Without DNA evidence linking the three players to the accuser, the woman’s testimony figures to be the key element of the prosecution’s case. Both Early and John Banzhaf, a professor at George Washington University Law School, said Friday that means the defense is sure to make the dismissal of the rape charge — and what it implies about her credibility — an issue at trial.

Banzhaf said no jury is likely to believe a witness who for months contended she had been raped, but now isn’t sure.

“This is the beginning of the end,” Banzhaf said. “If they couldn’t make the rape case, I don’t see how they could make the others.”

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Seligmann, Finnerty and Evans insist they are innocent. Their attorneys have repeatedly called on Nifong to drop the case, citing the lack of DNA evidence, criticizing how police conducted a photo lineup and maintaining that the accuser, a 28-year-old student at North Carolina Central University, has given investigators at least a dozen different versions of the alleged assault.

“What we have now, ladies and gentlemen, is a prosecutor who says his case rises and falls on the statement of the accuser and (he) is going forward with a case when he knows he has multiple, different, contradictory statements from that person,” defense attorney Joseph Cheshire said Friday.

In dropping the rape charges, Nifong did not specify what sex acts authorities now believe occurred, and defense attorneys said Friday they don’t have a clear idea of what the prosecutor will present at trial.

Nifong hasn’t return repeated messages seeking comment. In an October 30 interview with The Associated Press, he said he felt a “responsibility” to prosecute the case.

In an interview with The New York Times published Saturday, Nifong said the “case will go away” if the accuser ever says one of the players she identified did not attack her. He also said he wasn’t surprised the defense had focused on the accuser.

“If you can keep the victim from coming to court, if you make the victim say, ’Gee, this isn’t worth it,”’ he told the Times.

Nifong’s commitment to case and the accuser, Coleman said, shouldn’t come as a surprise.

“To all of a sudden drop it and admit he doesn’t have evidence to proceed to trial would be a fairly damning admission. I don’t expect that to happen,” Coleman said. “On the other hand, I don’t think the case has credibility. How can anyone believe there’s evidence to support the remaining charges?”