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.
Soon after, horrifying sounds and images flooded TV screens and Internet sites across America. SWAT teams in flak jackets swarmed the campus. Students helped faculty members carry out the wounded, as ambulances streamed to the site.
CNN showed a jerky video provided by a student's cell phone that showed what seemed to be police outside Norris Hall accompanied by a chilling soundtrack - the crackle of gunshots.
What had happened inside? Reports were fragmentary.
One student told the Washington Post that the gunman, said to be about 19 years old, burst into the room and fired about 30 shots in just a minute and a half - first blasting a professor in the head, then shooting the students.
Planet Blacksburg - a local, student-run Web site - quoted Ruiqi Zhang, identified as a computer engineering student who said he was on the second floor of Norris.
"A student rushed in and told everybody to get down," Zhang said. "We put a table against the door and when the gunman tried to shoulder his way in and when he saw that he couldn't, he put two shots through the door. It was the scariest moment of my life."
The Web site also quoted Gene Cole, a building worker, as saying the shooter wore a hat and carried an automatic weapon. "He loaded his gun at me," Cole said. "I ran down the steps to get out of there."
It was eerily reminiscent of the shootings at Columbine High School in Colorado eight years ago this very week. And something else recalled some of the most shocking images of Sept. 11, 2001: Students jumping from windows to escape.
Virginia Tech sent out a third e-mail at 10:17 a.m. announcing classes were canceled and repeating the warning for everyone to lock their doors and stay away from windows.
By then, the magnitude of this bloody day was becoming increasingly clear.
Grim-faced TV anchors reported the rising death toll: 21, 31, then 33, including the shooter himself, not immediately identified. He put a bullet to his head. Two of the dead were shot at the dorm, the remainder at Norris Hall. Authorities also reported that 15 people were wounded, some seriously.
At 10:53 a.m. - more than three-and-half hours after the terror began - the announcement of the end of the worst mass shooting in U.S. history came in a fourth e-mail from the school.
"Subject: Second Shooting Reported; Police have one gunman in custody
"In addition to an earlier shooting today in West Ambler Johnston, there has been a multiple shooting with multiple victims in Norris Hall.
"Police and EMS are on the scene.
"Police have one shooter in custody and as part of routine police procedure, they continue to search for a second shooter."
"All people in university buildings are required to stay inside until further notice. "All entrances to campus are closed."
As the wind whipped through the campus on Monday night, a steady stream of students from West Ambler Johnston carried suitcases, backpacks and other personal items - one held a large stuffed dog nicknamed Hokie after the school mascot - to find someplace else in sleep.
They said they couldn't bear to spend the night in the dorm.