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The fraternity at the center of a Rolling Stone article alleging a gang rape at its University of Virginia chapter last fall demanded that the magazine retract the article Monday after police said they couldn't substantiate the claim.

"We have no basis to conclude that anything happened at that fraternity house," Charlottesville Police Chief Timothy Longo told reporters.

He said the student, identified in the article as Jackie, refused to give a statement or answer questions when she met with police in December, two weeks after the article was published.

In the article, "A Rape on Campus," Jackie described being attacked by seven men in a dark room at a Phi Kappa Psi fraternity party when she was a freshman, in September 2012. She said some of her friends urged her not to report the crime.

Rolling Stone backed away from the story and ultimately apologized for it after major elements were disputed by The Washington Post and other news outlets. The magazine said it had never contacted the man who was alleged to have orchestrated the sexual assault.

Longo said that police found no evidence that any party took place at Phi Kappa Psi on the night in question.

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He stressed that the conclusion did not mean that "something terrible didn't happen to Jackie," only that police could not corroborate it. He characterized the investigation as suspended, not closed.

"I'm not in a position where I can say, based on all the evidence that we've developed, that something terrible didn't happen to that young lady that night," he said. "All I can tell you is there's no substantive basis to conclude that what is described in that article happened that night."

"That Rolling Stone sought to turn fiction into fact is shameful," the fraternity said in a statement Monday night from its Indianapolis headquarters. "The discredited article has done significant damage to the ability of the Chapter's members to succeed in their educational pursuits, and besmirched the character of undergraduate students at the University of Virginia who did not deserve the spotlight of the media."

The fraternity asked Rolling Stone to "fully and unconditionally" retract the story and remove it from its website.

Palma Pustilnik, a legal aid lawyer who has spoken for Jackie, declined comment.

The police chief also said that he hoped there would be no "chilling effect" discouraging women from coming forward to report sexual assault.

After the article appeared, the university suspended all fraternity activities for two months. The university reinstated Phi Kappa Psi in January and said that police had yet to find corroboration for the account.

"We look forward to working with all fraternities and sororities in enhancing and promoting a safe environment for all," the university president, Teresa A. Sullivan, said at the time.

The Columbia University graduate school of journalism is conducting a review on behalf of the magazine. The managing editor said over the weekend that Rolling Stone would publish the results.

The Charlottesville campus has been roiled this academic year — not just by the magazine story but by the killing of a sophomore and the bloody arrest of a student outside a bar last week.

M. Alex Johnson of NBC News contributed to this report.