A map shows the location of the sites of the two separate attacks at Virginia Tech university. 1. 0715, shooting reported at the dormitory building. 2. About two hours later a further shooting is reported. Photo by BBC
Survivors of the worst shooting rampage in US history have criticised authorities for waiting too long to alert people a gunman was on the loose, BBC reported.
The rampage at Virginia Tech university killed at least 33 including a suspected gunman.
There were two hours between the two separate attacks, the second of which saw 31 deaths, and students have asked why the campus was not locked down.
University officials said they could not have foreseen the second incident.
A student who survived by pretending to lie dead on a classroom floor told CNN that the gunman, an Asian male, was dressed "almost like a Boy Scout".
"He just stepped within five feet of the door and just started firing," said Erin Sheehan, who was in one of the Norris Hall classrooms where the second shooting incident took place.
Sheehan described the gunman -- who later shot and killed himself, according to police -- as a young man wearing a short-sleeved tan shirt and black ammunition vest.
"He seemed very thorough about it -- getting almost everyone down -- I pretended to be dead," she said.
"He was very silent," said Sheehan, one of only four students in her 25-student German class who were not shot.
The gunman left but returned in about 30 seconds. "I guess he heard us still talking," said Sheehan.
"We forced ourselves against the door so he couldn't come in again, because the door would not lock."
The man tried three more times to force his way in and then began firing through the door, she said.