WEST LAFAYETTE Ind.

Officials don't know why someone left a noose made from a sweatshirt hood drawstring hanging in a Purdue University library.

The noose was found at the Humanities, Social Sciences and Education library in Stewart Center about 11:30 p.m. Sunday, said university spokesman Joe Bennett. An employee found the 18-inch-long noose hanging from a hole in a desk backboard in an isolated study area.

"The noose was small and wasn't left in an area where it would have been generally visible," said Lt. Fred Davis, a Purdue police detective.

"Given the circumstances and the currently available evidence, it is not possible to interpret the intent of the individual who left this object in the library."

Police are investigating the incident, which occurred a few days after a "Jena Six" rally.

The six black teens known as the "Jena Six" were arrested after a December 2006 attack on Justin Barker, who was knocked unconscious.

Their case fueled allegations that prosecutors were treating blacks more harshly than whites, because charges weren't filed against three white teens accused of hanging nooses in a tree at the high school shortly before the attack.

Nooses, a racially charged symbol of the lynching violence of the segregation era, have also turned up recently on the office door of a black professor at Columbia University, in a tree at Indiana State University, and in a Coast Guard cadet's bag.

Deen King Smith, a former president of the Black Graduate Association, said the incident was disappointing.

"It could be ignorance, it could be someone think it's funny or cute, but at the end of the day, it's really sad," he said. "Especially at an institution such as Purdue."

Information from: Journal and Courier, http://www.jconline.com