Why the U.S. has the most mass shootings

When a gunman opened fire Wednesday on two Virginia journalists and the woman they were interviewing on live TV, he was influenced by a long history of public mass killings throughout the country. Shooter Vester Lee Flanagan II said he admired mass shooters like those at Columbine High School in 1999 and Virginia Tech in 2007, and that he put down a deposit for a gun two days after the Charleston, South Carolina, church shooting in June.