“You could think of domestic violence as a canary in the coal mine for future violence,” says Sarah Tofte, director of research and implementation at Everytown for Gun Safety. “We may not know everything we need to know about why and when it reverberates outside the home, but we know that it does, and we’ve seen it over and over again.”

Several recent mass shooters share Kelley’s record of domestic violence. James Hodgkinson, who injured Republican Rep. Steve Scalise of Louisiana and several others when he opened fire on lawmakers and aides at a baseball practice in June, had been arrested in 2006 for hitting and choking his daughter. Omar Mateen, who killed 49 people in the Pulse nightclub massacre in Orlando last June, had an abusive relationship with his ex-wife, who said he frequently beat her. Robert Dear, who killed three people and wounded nine others when he opened fire on a Planned Parenthood clinic in Colorado in 2015, had been accused of domestic violence by two of his ex-wives. He was also arrested for rape in 1992. (There is no record Dear was convicted, suggesting the charge was ultimately dismissed.)