Police were grappling Friday with two separate incidents of someone stringing up nooses in public places — one at Columbia University and another outside a ground zero post office damaged in the Sept. 11 attacks.
New York Police Department spokesman Paul Browne said there were no suspects in either incident, which both occurred this week on opposite ends of Manhattan.
At Columbia, detectives were still reviewing 56 hours of security camera images captured by seven security cameras in and around the building where the noose was discovered early Tuesday morning hanging from the doorknob of a black professor's office, Browne said.
In the second case, a noose was discovered Thursday dangling from a lamppost near the lower Manhattan post office. Building managers removed the noose, which was later turned over to the NYPD's hate crimes unit for investigation, police said.
"At this point, there was no target that was evident or any motive," U.S. Postal Inspection Service spokesman Al Weissman said Friday morning. He said no postal workers had reported any threats or other problems.
The post office at 90 Church St. was closed for nearly three years after the 2001 terrorist attacks, which left the 15-story building contaminated with asbestos, mercury and debris from the fallen twin towers.
Students, faculty and administrators at Columbia have denounced the attack on professor Madonna Constantine, 44, a professor of education and psychology who has written extensively about race.
Police were testing the 4-foot-long piece of twine for DNA evidence and interviewing students and faculty.
Among those questioned was another Teachers College professor, Suniya S. Luthar, who had feuded with Constantine; police said she was not considered a suspect.
Meanwhile, police were called to the Ivy League campus again Thursday to probe another troubling discovery — a caricature of a yarmulke-wearing man and a swastika found on a university bathroom stall door.
The hate crime unit was investigating the black-ink drawing, but police said there was no reason to believe the two incidents were linked.
University President Lee Bollinger said the sketch was promptly removed, adding that he was reluctant to call attention to such drawings because he did not want to "broadcast, in any way, the message they attempt to send or empower those behind them."
Nooses, charged with symbolism of lynchings in the Old South, have appeared in recent incidents around the country. Three white students hung nooses from a big oak tree outside a high school last year in Jena, La., fueling racial tensions. More recently, nooses have been found at the U.S. Coast Guard Academy in New London, Conn., and the Hempstead Police Department's locker room on Long Island.