https://www.cnn.com/2013/10/31/us/virginia-tech-shootings-fast-facts/index.html
Timeline:
December 13, 2005 - Cho is ordered by a judge to seek outpatient care after making suicidal remarks to his roommates. He is evaluated at Carilion-St. Alban's mental health facility.
February 9, 2007 - Cho picks up a Walther P-22 pistol he purchased online on February 2 from an out-of-state dealer at JND Pawn shop in Blacksburg, across the street from Virginia Tech.
March 2007 - Cho purchases a 9mm Glock pistol and 50 rounds of ammunition from Roanoke Firearms for $571.
April 16, 2007 - 7:15 am - Police are notified in a 911 call that there are at least two shooting victims at West Ambler Johnston Hall, a four-story coed dormitory on campus that houses approximately 895 students.
9:01 am - Cho mails a package containing video, photographs and writings to NBC News in New York City. NBC doesn't receive it until two days later due to an incorrect address on the package.
9:26 am - The school sends out an email statement that a shooting took place at West Ambler Johnston Hall earlier that morning.
9:45 am - 911 calls report a second round of shootings in classrooms at Norris Hall, the engineering science and mechanics building. At least 32 students and faculty are killed.