Reports Of Nooses Appearing Across U.S., As Police Investigate Episode At Columbia University, A Rash Of Other Incidents Reporte

Police were exploring whether a noose left on a black professor at Columbia University professor's office door could have been the work of a disappointed student or a hostile colleague, a police official said.

Authorities were testing the 4-foot-long twine noose for DNA evidence, but had no suspects in the highly charged episode at the Ivy League campus.

"I'm upset that our community has been exposed to such an unbelievably vile incident," the professor, Madonna Constantine, told hundreds of faculty and students who held a raucous rally Wednesday. She described the incident as a "blatant act of racism" and said it "reeks of cowardice and fear."

Nooses - reviled as symbols of lynchings in the Old South - have been showing up in other incidents around the country lately. 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.

Morris Dees, founder and chief legal counsel for the Southern Poverty Law Center, has been tracking incidents like this for 35 years.

"It's popping up all over the place," Dees told CBS Early Show Co-Anchor Harry Smith. "I think maybe Jena, Louisiana, possibly has caused some copycat situations."

Thousands of demonstrators, including the Revs. Jesse Jackson and Al Sharpton, converged on Jena on Sept. 20 to decry what they called a racist double standard in the justice system. They protested the way six blacks were arrested on attempted murder charges in the beating of a white student, while three whites were suspended but not prosecuted for hanging nooses in a tree in August 2006.

The noose evokes the lynchings of the Jim Crow South and "is a symbol that can be deployed with no ambiguity. People understand exactly what it means," said William Jelani Cobb, a professor of black American history at Spelman College in Atlanta.