On a university campus of 2,600 acres (1,050 hectares), with more than 26,000 students, ironclad security is not a practical goal. Even so, tough questions swiftly surfaced as to how effectively Virginia Tech authorities responded to Monday's horrific massacre that left 33 people, including the shooter, dead.
Why were campus police so sure the threat was contained in one dormitory, when most of the killings occurred two hours later in a classroom building?
Why did they think the assailant might have left the campus after those initial shootings that killed two?
Why was there a lag of more than two hours after the first shootings before an alarm was e-mailed campuswide - around the time another, more deadly burst of carnage occurred? And more generally, some security experts wondered, was the school's crisis planning and emergency communications system up to the task?
Clearly, something went terribly wrong.
Bombarded with security questions at a news conference, Virginia Tech President Charles Steger said authorities believed the shooting at the West Ambler Johnston dorm, first reported about 7:15 a.m. (1215 GMT), was a domestic dispute and mistakenly thought the gunman had fled the campus.
"We had no reason to suspect any other incident was going to occur," he said.
The dormitory was locked down immediately after the shooting, Steger said, and a phone bank was activated to alert the resident advisers there so they could go door-to-door warning the 900 students in the dorm. Security guards deployed at the dorm, he said, and others began a sweep across campus.
Asked why he did not order a lockdown of the entire campus, Steger noted that thousands of nonresident students were arriving for 8 a.m. (1300 GMT) classes, fanning out across the sprawling campus from their parking spots.
"Where do you lock them down?" Steger asked.
He said security on campus will be tightened now, but offered no details.
"We obviously can't have an armed guard in front of every classroom every day of the year," he said.
Overall, Steger defended the university's response, saying: "You can only make a decision based on the information you know at that moment in time. You don't have hours to reflect on it."
Some students were upset that the gunman was able to strike a second time, saying the first notification they got of the shootings came in an e-mail at 9:26 a.m. (1326 GMT). The e-mail mentioned a "shooting incident" at West Amber Johnston, said police were investigating, and asked students to be cautious and contact police about anything suspicious.
Security experts not connected with Virginia Tech said their immediate questions focused on whether the university had adopted and practiced a plan to handle such dire crises, and whether its system of emergency communications was state-of-the-art.
"It is critical for them to have solid emergency plans in place to deal with crisis situations," said Kenneth Trump of National School and Safety Services in Cleveland. "The key is to have a solid communications component in place to deal with notifying students, parents, faculty, staff and the media whets going on."
Michael Dorn of Safe Havens International in Macon, Georgia, which has advised many universities on security measures, said campus emergency plans can be ineffective unless staff and students are trained on how to cooperate.
"They can make the difference between one or two people being victimized and larger numbers," Dorn said.
It was second time in less than a year that the Virginia Tech campus was closed because of a shooting.
Last August, the opening day of classes was canceled and the campus closed when an escaped jail inmate allegedly killed a hospital guard off campus and fled to the Tech area. A sheriff's deputy involved in the manhunt was killed on a trail just off campus. The accused gunman, William Morva, faces capital murder charges.
As for other crime on campus, Virginia Tech reported just eight arrests for illegal weapons possession from 2003-05, according to statistics posted by the U.S. Department of Education.
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