There are signs.
That's the message Sandy Hook Promise wants to get out to schools -- most teenagers make a warning of some kind before going on a shooting rampage, according to the Centers for Disease Control.
"The essence of the program, basically, is about being a good upstander, not just being a bystander," said Mark Barden from Sandy Hook Promise. He lost in son, Daniel, in the 2012 shooting in Newtown, and he's talking about program called Say Something.
Its focus is on creating what Barden calls a culture of awareness. The program teaches students to learn how to recognize warning signs of violence and self harm, which in addition to bullying, can include eating disorders and emotional abuse.
"By cultivating this connected community idea," he said, "then we will be averting tragedies, specifically gun-related tragedies, but really all violence should be coming down."
There's a special emphasis on social media, he said, which is a place where bullying can be especially harsh and anonymous, making it difficult to combat.
This is also tied to the concept of social and emotional learning, which has been growing in popularity in schools across Connecticut since the Sandy Hook tragedy. Barden's group also has a program called Start with Hello, which addresses social isolation.
"It trains kids to reach out to somebody who's chronically isolated, and make them feel included and connected," he said.
Strong social and emotional learning programs have been shown to help students adapt and become more productive and happier adults.