Authorities declared the campus safe and lifted a lockdown after a nearly four-hour manhunt, seeming to lend credence to television news reports that a body found in a Virginia Tech parking lot was that of the shooter.

Police at a televised news conference declined to say whether they suspected a murder-suicide and offered no motive for the crime, citing an ongoing investigation.

The place where the officer was shot is in a parking lot in the shadows of the Virginia Tech football stadium. Small groups of students stood nearby as police removed yellow tape from around the crime scene this evening.

The incident evoked grim memories of April 2007 when a mentally deranged student killed 32 people and wounded 25 before committing suicide on the school's rural campus in the Shenandoah Valley about 250 miles from Washington. It was the deadliest attack by a single gunman in US history.