The Worst Mass School Shootings in Modern American History

The 10 people killed at Santa Fe High School in Texas are the latest victims of what seems to be an epidemic of mass shootings across the United States, many of which playing out inside our nation's schools. Eight students and two teachers were allegedly killed by a teen who is now in police custody. Just three months ago, 17 people were killed at Marjorie Stoneman Douglas High School in Florida. InsideEdition.com's Mara Montalbano (https://twitter.com/MaraMontalbano) has more.