STATE POLICE SAY the gunman who killed himself at Virginia Tech acted alone in the slaying of a campus police officer.
Police spokeswoman Corinne Geller says the gunman ran from the scene and changed clothes before killing himself in a parking lot a half-mile away.
Geller says the gunman, whose identity has not been released, was later found by an officer in the campus parking lot. The man shot and killed himself. Geller said at a Thursday news conference that the gunman put his clothes in a backpack and left it behind at a greenhouse on campus.
Geller says investigators are still trying to find out why the gunman ambushed the officer, Deriek W. Crouse.
The officer who was shot dead in his parked cruiser was a trained firearms and defense instructor with a specialty in crisis intervention.
The campus shooting prompted officials to lock down the university for hours Thursday while police and SWAT teams searched the school, the scene in 2007 of the deadliest mass shooting in modern US history when 32 people were shot dead and dozens more injured.
More:Â Two dead after shooting on Virginia Tech campus >
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