New York police were investigating several possible hate crimes Friday as they began reviewing dozens of hours of surveillance camera images they hope will help them find the person who hung a noose on a black Columbia University professor's office door.
Columbia University gave the security tapes to police Thursday afternoon after initially refusing to hand them over, New York Police Department Deputy Commissioner Paul Browne told ABC News.
The NYPD, which is investigating the incident at Teachers College as a possible hate crime, is also testing the noose for DNA evidence. The U.S. Department of Justice has opened an investigation into the incident and the New York attorney general's office is looking into the case.
Police were also investigating two other possible hate crimes Friday, including another one at Columbia. A drawing of a yarmulke-wearing man and a swastika was found on a bathroom stall door at the Ivy League school Thursday, police said. Investigators said there was no reason to believe the two incidents were linked.
Also on Thursday, post office workers discovered a noose hanging from a light pole outside a post office in downtown Manhattan near ground zero, Al Weissman of the U.S. Postal Inspection Service told ABC News.
Weissman said postal workers had not received any threats and it was not clear if the noose was targeted at someone in particular.
Browne said Columbia turned over the security tapes in the noose incident Thursday after news reports emerged that the university had rebuffed police requests for the tapes.
A university spokeswoman said in a statement on Thursday, "The news reports are untrue. We are giving the tapes to the police." Teachers College President Susan Fuhrman said in a statement that the school had asked police to get a court order out of concern for students' privacy.
"There was no desire to hinder the investigation -- far from it," she said. On Wednesday, Furhman called the noose "an abhorrent act that has no place in this great institution."
The noose was first discovered hanging from the office door of professor Madonna Constantine Tuesday morning by one of Constantine's colleagues.
Constantine, a professor of psychology and education who specializes in issues of race and multiculturalism, told a crowd of more than 100 supporters at a rally Wednesday that the noose was a "blatant act of racism." Constantine is the director of the Cultural Winter Roundtable in psychology and education at Teachers College. She has written broadly on themes of multiculturalism, racism and ethnicity, according to a list of publications on her online faculty bio. Students said Constantine teaches a class on racial justice and described her as well-respected among the faculty and student body.
"Hanging a noose on my door reeks of cowardice and fear on many, many levels," she said, prompting cheers and applause from the crowd assembled outside the college's main entrance. "I would like the perpetrator to know I will not be silenced."
"It felt very personal and very degrading," Constantine told ABC's "Good Morning America."
Professor Derald Wing Sue, one of the first people to discover the noose, told ABC News that Constantine's immediate concern after finding the noose was "the possible negative impact it would have on students of color and the staff."
"That's very characteristic of her," he said.