Jan 22, 2010 4:46 PM by Associated Press
Carnegie Mellon University in Pittsburgh has lifted an evacuation of three buildings after an unspecified security threat.
Campus spokesman Ken Walters says the school received a phoned-in threat about noon Friday but reopened the buildings about 2:30 p.m.
Walters didn't know that the threat was. Police searched the buildings, but didn't find anything threatening.
The school alerted students to leave using a text messaging system that sends warnings to cell phones.