Gunfire erupted in a dormitory and classroom at Virginia Tech on Monday, killing at least one person and leaving 21 injured before a suspect was arrested, authorities said. The state university told students to stay inside and away from windows as police swept the campus and worked to establish whether the gunman acted alone, according to AP. A hospital spokeswoman said 21 students were treated for gunshot wounds and other injuries. On the Web site, Tech reported the shootings at opposite sides of the 2,600-acre (1,052-hectare) campus at West Ambler Johnston, a co-ed residence hall that houses 895 people, and said there were «multiple victims» at Norris Hall, an engineering building. All entrances to the campus were closed and classes canceled through Tuesday. Aimee Kanode, a first year student, said the shooting happened on the 4th floor of West Ambler Johnston dormitory, one floor above her room. Kanode's resident assistant knocked on her door about 8 a.m. to notify students to stay put. «They had us under lockdown,» Kanode said. «They temporarily lifted the lockdown, the gunman shot again.» «We're all locked in our dorms surfing the Internet trying to figure out what's going on,» Kanode said. It was second time in less than a year that the campus was closed because of a shooting. In August 2006, the opening day of classes was canceled and the campus closed when an escaped jail inmate allegedly killed a hospiMorva, faces capital murder charges.