The first crackle of gunfire shattered the Monday morning calm. It was 7:15 a.m. on the campus of Virginia Tech and an epic killing spree had just begun.

Snow was swirling on the windy April day and classes had not yet started when a murderous rampage that would shake the nation started in a coed dormitory, West Ambler Johnston, home to 895 people.

The first reports of trouble were tragic, but small in scope, no hint of the massacre about to unfold in the Blue Ridge mountains of Virginia: One person was dead, another injured.

The official word to students apparently did not come right away.

In a mass e-mail, Virginia Tech officials announced a shooting had occurred at the dorm, police were on the scene and urged anyone in the university community to "be cautious" and contact police if they saw anything suspicious or had information on the case.

The e-mail was signed off at 9:26 a.m.

Police would later say they thought the two had been shot in a domestic dispute. They thought the gunman had fled the campus.

"We secured the building, we secured the crime scene," Virginia Tech Police Chief Wendell Flinchum said. For a long while, there were no new reports of anything suspicious.

Classes on the Blacksburg, Va., campus had gone ahead as scheduled; the first period began at 8 a.m. The doors of the buildings remained open. And the heavily armed gunman with a motive yet unknown had set his sights elsewhere, at Norris Hall, an engineering building nearly a half-mile away on the 2,600-acre campus.

Police believe the shooting at Norris began around 9:45 a.m. The building's doors had been chained shut, possibly by the gunman, authorities said.

Brittany Zachar, an 18-year-old freshman who lives at West Ambler Johnston, decided to attend an economics class even though she saw a handwritten sign on pink paper posted in the dorm bathroom saying something had happened and going to class was optional.

As she walked on campus, she heard the pop of gunshots coming from the direction of Norris Hall. She saw police running.

"I heard the gunshots and just sprinted," she says, adding that she took cover in another school building. "It was probably one of the scariest things in my life."

At 9:55 a.m., the school sent out a second e-mail.

"Please stay put," it warned. "A gunman is loose on campus. Stay in buildings until further notice. Stay away from all windows."

The university also began telephoning resident advisers in the dorms to notify them and sent people to knock on doors to get the word out, Virginia Tech President Charles Steger said at a news conference.