The New York Police Department said Thursday that Columbia University has refused to voluntarily turn over security video that could help identify suspects in the case of a noose left on the office door of a black professor — a claim the school now denies.

Columbia told FOX News that there are no security cameras in professor Madonna Constantine's fourth-floor office or in the hallway, only in the lobby downstairs, and university officials are in the process of giving those tapes to authorities.

"The news reports are untrue. We are giving the tapes to the police," a representative from Columbia's Teachers College, where Constantine is a professor, said in an e-mail.

The source couldn't estimate how many tapes there are or how many the school planned to give to police.

Neither the NYPD nor Columbia could confirm to FOX News that the handover of the tapes had taken place, though The Associated Press reported that the school had turned the video over to investigators under pressure.

Teachers College, on the advice of its counsel, refused yesterday to voluntarily give up the tapes without a court order. The NYPD claims the school reversed itself today.

A Teachers College spokeswoman said privacy laws required it to demand a court order. Since a subpoena was obtained, the school gave them the video, according to the AP.

Investigators began asking on Wednesday for tapes from cameras in the building where the incident occurred, but were initially rebuffed by administrators, Paul Browne, the New York Police Department's top spokesman, said earlier Thursday.

Authorities were testing the 4-foot-long twine noose for DNA evidence, but they had no suspects in the case, which rocked the Ivy League campus.

Police ruled out any possibility that the target of the attack had hung the rope herself.

"Our victim is a victim," Deputy Inspector Michael Osgood, commander of the hate crimes unit, said at a news conference Wednesday.

Federal officials, meanwhile, opened their own investigation into the incident.

"The Department of Justice — including the FBI, the U.S. Attorney's Office and the Civil Rights Division — has opened an investigation into this matter, and we will coordinate with the New York Police Department hate crimes task force, which is already investigating," a source within the DOJ told FOXNews.com in an e-mail.

Students, faculty and administrators denounced the attack on Constantine, a professor of education and psychology who has written extensively about race.

Constantine spoke to hundreds of faculty and students at a raucous rally Wednesday, calling the gesture a "blatant act of racism." Several similar incidents have happened recently around the country.

Last year in Jena, La., three white students hung nooses from a big oak tree outside the high school, inflaming racial tensions. Other nooses have cropped up at the U.S. Coast Guard Academy and the Hempstead Police Department locker room.

Teachers College held a community meeting Wednesday to discuss the incident, which comes on the heels of Iranian President Mahmoud Ahmadinejad's inflammatory visit to the school and the recent discovery of racist graffiti in the bathroom of a campus building.

Teachers College, founded in 1887, describes itself as the nation's oldest and largest graduate school of education.

FOXNews.com's Catherine Donaldson-Evans and the Associated Press contributed to this report.