School shootings, mass killings are 'contagious,' study finds

By Ben Smart, Special to CNN

Updated 2247 GMT (0647 HKT) November 3, 2015

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Parents wait for news after a shooting at Marjory Stoneman Douglas High School in Parkland, Florida, on Wednesday, February 14.<a href="https://www.cnn.com/2018/02/14/us/florida-high-school-shooting/index.html" target="_blank"> At least 17 people were killed at the school</a>, Broward County Sheriff Scott Israel said. The suspect, 19-year-old former student Nikolas Cruz, is in custody, the sheriff said. The sheriff said he was expelled for unspecified disciplinary reasons.
Photos: Worst mass shootings in the United States
Parents wait for news after a shooting at Marjory Stoneman Douglas High School in Parkland, Florida, on Wednesday, February 14. At least 17 people were killed at the school, Broward County Sheriff Scott Israel said. The suspect, 19-year-old former student Nikolas Cruz, is in custody, the sheriff said. The sheriff said he was expelled for unspecified disciplinary reasons.
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Investigators at the scene of a mass shooting at the First Baptist Church in Sutherland Springs, Texas, on Sunday, November 5, 2017. <a href="http://www.cnn.com/2017/11/06/us/devin-kelley-texas-church-shooting-suspect/index.html" target="_blank">A man opened fire inside the small community church,</a> killing at least 25 people and an unborn child. The gunman, 26-year-old Devin Patrick Kelley, was found dead in his vehicle. He was shot in the leg and torso by an armed citizen, and he had a self-inflicted gunshot to the head, authorities said.
Photos: Worst mass shootings in the United States
Investigators at the scene of a mass shooting at the First Baptist Church in Sutherland Springs, Texas, on Sunday, November 5, 2017. A man opened fire inside the small community church, killing at least 25 people and an unborn child. The gunman, 26-year-old Devin Patrick Kelley, was found dead in his vehicle. He was shot in the leg and torso by an armed citizen, and he had a self-inflicted gunshot to the head, authorities said.
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A couple huddles after shots rang out at a country music festival on the Las Vegas Strip on Sunday, October 1, 2017. At least 58 people were killed and almost 500 were injured when <a href="http://www.cnn.com/2017/10/02/us/las-vegas-shooter/index.html" target="_blank">a gunman opened fire</a> on the crowd. Police said the gunman, 64-year-old Stephen Paddock, fired from the Mandalay Bay hotel, several hundred feet southwest of the concert grounds. He was found dead in his hotel room, and authorities believe he killed himself and that he acted alone. It is the deadliest mass shooting in modern US history.
Photos: Worst mass shootings in the United States
A couple huddles after shots rang out at a country music festival on the Las Vegas Strip on Sunday, October 1, 2017. At least 58 people were killed and almost 500 were injured when a gunman opened fire on the crowd. Police said the gunman, 64-year-old Stephen Paddock, fired from the Mandalay Bay hotel, several hundred feet southwest of the concert grounds. He was found dead in his hotel room, and authorities believe he killed himself and that he acted alone. It is the deadliest mass shooting in modern US history.
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