Virginia Tech massacre
The Virginia Tech massacre took place on April 16, 2007, on the campus of Virginia Polytechnic Institute and State University in Blacksburg, Virginia, United States. Seung-Hui Cho shot killed 32 people and wounded 17 others in two separate attacks, approximately two hours apart, before committing suicide. (Another 6 people were injured escaping from classroom windows.) The massacre is the deadliest shooting incident by a single gunman in U.S. history and one of the deadliest in the world.

Seung-Hui Cho, was a senior English major at Virginia Tech, had previously been diagnosed with a severe anxiety disorder. During much of his middle school and high school years, he received therapy and special education support. After graduating from high school, he enrolled at Virginia Tech. Because of federal privacy laws, Virginia Tech was unaware of Cho's previous diagnosis or the accommodations he had been granted at school. In 2005, Cho was accused of stalking two female students. After an investigation, a Virginia special justice declared Cho mentally ill and ordered him to attend treatment. Lucinda Roy, a professor and former chairwoman of the English department, had also asked Cho to seek counselling.

Cho used two guns, a 22-caliber Walther P22 semi-automatic handgun and a 9 mmsemi-automatic Glock 19 handgun. His shootings occurred in separate incidents, with the first at West Ambler Johnston Hall, where he killed two pupils, and the second at Norris Hall, where the other 31 deaths, including himself, and caused 23 people to be injured.

Cho shot his first two victims around 7:15 a.m. in West Ambler Johnston Hall. Cho left the scene and returned to his dorm room. While police and emergency medical services units were responding to the shootings in the dorm next door, Cho changed out of his blood-stained clothes, logged on to his computer to delete his e-mail, and then removed the hard drive. Almost two hours after the first killings, Cho appeared at a nearby post office and mailed a package of writings and video recordings to NBC News, and then went to Norris Hall. In his backpack, he carried several chains, locks, a hammer, a knife, two handguns with nineteen 10- and 15-round magazines, and almost 400 rounds of ammunition.

Cho entered Norris Hall and chained the three main entrance doors shut. He placed a note on at least one of the chained doors, claiming that attempts to open the door would cause a bomb to explode. Shortly before the shooting began, a faculty member found the note and took it to the school's administration. At about the same time, Cho had begun shooting. The first 911 call was received within one or two minutes of the first shots. His first attack happened in advanced hydrology