AUSTIN, Texas (AP) - Police are letting students leave campus after a gunman opened fire then killed himself inside a library at the University of Texas at Austin. The campus of about 48,000 students has been on lockdown for several hours. Austin police Cpl. Scott Perry says students are being allowed to leave but that police are still preventing anyone from entering the campus. Perry says police are still searching for a possible second suspect. Campus police spokeswoman Rhonda Weldon says no one else was hurt in the shooting Tuesday morning at the Perry-Castaneda Library. Investigators are trying to determine what sparked the gunfire.