There’s a familiar refrain after almost every shooting that makes national news: “The shooter had a history of domestic violence.”

The shooter who opened fire on a congressional baseball practice in June, seriously wounding Rep. Steve Scalise, had allegedly physically attacked his daughter and been arrested for domestic battery. The man who shot and killed 49 people and injured 53 more at a gay nightclub in Orlando had beaten his ex-wife. And last month in Dallas, the man who stormed into his ex-wife’s home and killed her and seven others had been violent with her at least twice, smashing her face against a wall.

And now, after the mass shooting in Las Vegas—the worst mass shooting in modern American history—media reports indicate that that the gunman was known to be verbally abusive to his girlfriend.

There is a consistent and undeniable link between mass shootings and domestic violence. As a woman, a mother of four young women, a feminist, and an American, this trend concerns me deeply. I founded the nation’s largest grassroots gun violence–prevention organization, Moms Demand Action for Gun Sense in America, the day after 20 first graders and six educators were shot and killed at Sandy Hook Elementary School. I’ve been tracking gun violence closely ever since.

Less than five years have passed since the horrific shooting at Sandy Hook. In that time, there have been 85 mass shootings (using the definition of four or more people shot and killed, not including the shooter), according to research by Everytown for Gun Safety. And research shows that 54 percent of mass shootings are tied to domestic or family violence—meaning that the shooter kills a current or former intimate partner or other family member.

In many cases, those other family members are children. Shockingly, 25 percent of mass shooting fatalities are children age 17 or younger. And frequently a mass shooting looks less like what we saw in Las Vegas and more like an abusive man (it’s almost always a man) who decides to murder his entire family.

In July 2017 in Maine, a man shot his wife, child, and a neighbor before being killed by police. In August 2016, a man shot and killed his wife and their three young children—ages 2 to 8—before fatally shooting himself in Sinking Spring, Pennsylvania. In June 2016 in Las Vegas, a man fatally shot his wife outside a Walgreens store. He then fatally shot their three children—ages 9 to 15—in the family’s apartment before fatally shooting himself. The list of similar incidents is appallingly long and unrelentingly tragic.