Virginia Tech used alert system to update campus after police officer shot

Thursday, December 8, 2011 | 9:29 p.m. CST; updated 9:48 p.m. CST, Thursday, December 8, 2011

BLACKSBURG, Va. — A gunman killed a police officer in a Virginia Tech parking lot Thursday and then apparently shot himself to death nearby in a baffling attack that shook up the campus nearly five years after it was the scene of the deadliest shooting rampage in modern U.S. history.