Other Big Ten police departments are also turning to online materials when investigating on-campus criminal activity.

Purdue University detective lieutenant of investigations Fred Davis said some officers have accounts on Facebook.com that are used to supplement investigations.

"If we have people involved in some criminal activity and we only know the first name of someone, usually we can identify them through Facebook.com," he said.

Larry Langley, associate director of the University of Iowa Department of Public Safety, said Iowa police use Facebook as one of many different tools in investigations.

"If we were trying to identify someone and we had information that we could find on the Internet through Facebook.com, that would be a tool just like any other investigative lead," he said.

Langley compared the department's use of Facebook to using a phonebook; if they know a name and a place of residence, they could use either as a resource, he said.

Police at other Big Ten schools have heard of Facebook but have not used it in investigations. Michigan State University police enlisted the help of the East Lansing Police Department after a 1999 riot. The department established a "wall of shame" --composed of photographs contributed by members of the media and some individuals during the riot. Dave Trexler, deputy chief of the Michigan State Police, said using the wall was successful.

"We had a tip line with a reward set up for information leading to arrests and convictions," he said.

Trexler said he doesn't think the department would use Facebook for an investigation.

"There's just so many other sources to follow up to get information. Each of us do things a little bit differently in various areas," he said.

Sgt. Craig Munroe of the Indiana University Police Department said Facebook has not been used in investigations, but officers would use any method that is "legal and moral."

"That's public information," he said. "Why couldn't the police department use that?"

Munroe said he thinks students should be more careful about what they put on the Internet.

"It seems kind of reckless to do something like that; it's not well thought out," he said, referring to the Penn State Facebook groups whose members say they rushed the field after the Oct. 8 Ohio State game.

Police officials at other Big Ten schools also said students should understand the implications of posting personal information on the Internet.

"If you have posted your information out on the Internet, you have become a matter of public record," said Diane Brown, a University of Michigan campus police spokeswoman. "Identification of yourself is then an open book and can be used for numerous purposes."