“I don’t think there’s ever been an incident that I’ve learned about or read about that has somebody waking up — whether it’s in a school or a workplace — and saying, ‘Oh, this is a good day to pick up a gun and shoot a bunch of people. There’s usually bubbling grievances to the surface. The trick is to catch those things early,” said Marc Zimmerman, professor of public health and psychology, and co-director of the Institute for Firearm Injury Prevention and the National Center for School Safety.

Dr. Zimmerman spoke with The New York Times about the importance of prevention efforts in terms of identifying signs for those at risk of harming themselves or others.