When James Alex Fields Jr. allegedly rammed his car into a crowd protesting a white nationalist rally in Charlottesville, Virginia, and killed a woman on Saturday, it was not the first time he was accused of violent behavior.

In 2010, his mother, Samantha Bloom, told police that her son hit her in the head, covered her mouth with his hands and threatened to assault her after she told the young teen to stop playing video games, according to The Washington Post.

The following year, the police were called twice. In October 2011, Bloom, who is disabled and uses a wheelchair, called 911 to report that Fields was being very threatening toward her, the dispatcher wrote. The next month, police were requested after Fields allegedly spat in his mothers face and stood behind her with a 12-inch knife.

If this is sounding familiar, it should: A history of domestic violence is a common thread linking many mass killers and violent terrorists.

Take Mohamed Lahouaiej Bouhlel, who drove his truck into a crowd gathered for a Bastille Day fireworks display in Nice, France, last year. He too had been accused of abusing his mother , as well as his wife.

Or Omar Mateen, the man who last year opened fire in a nightclub in Orlando, Florida , committing the deadliest mass shooting in modern U.S. history. He also allegedly beat his former wife, and his widow who is facing charges related to the nightclub attack says he physically abused her too .

Robert Dear, the man accused of shooting up a Planned Parenthood clinic in Colorado Springs and killing three in 2015, allegedly abused multiple wives .

Esteban Santiago, the man charged with killing five unsuspecting travelers in a mass shooting at Fort Lauderdale-Hollywood International Airport in January, was previously accused of assaulting his girlfriend including strangling her .

James T. Hodgkinson, who opened fire on Republican politicians at a congressional baseball practice this summer and wounded five people, had been accused of strangling and beating his foster daughter .

According to research by CNN national security analyst Peter Bergen, it is quite common for individuals who commit acts of political violence in the U.S. to have a history of domestic violence. As he wrote in a CNN op-ed , of the 48 perpetrators of lethal political violence in the U.S. since 9/11 whether they were motivated by jihadist, far right or black nationalist ideologies 11, or almost a quarter, had allegations or convictions of domestic violence or sexual crimes in their past.

In addition, most mass shootings in the U.S. constitute domestic violence to some greater or lesser degree.

Family or domestic violence played a role in at least 54 percent of mass shootings between 2009 and 2016, according to an Everytown for Gun Safety analysis. A mass shooting is defined here as an incident in which at least four people were fatally shot, not including the perpetrator. In these cases, its not uncommon for friends, neighbors and strangers to become casualties alongside the abusers family members.

Its important to note that domestic violence occurs too frequently in the general population to make it, on its own, a reliable predictor for acts of mass carnage. Millions of abusers across the U.S. terrorize their families, and very few will graduate to attacking others.

So the problem is: How do we identify which abusers are at risk of committing acts of heinous violence against the public? It may not be as impossible as it sounds. Researchers have already worked out how to determine which abusive men are most likely to murder their partners , and a growing number of jurisdictions now screen abused women for those warning signs.

If we truly want to reduce violence in the U.S., we must pay more attention to the horrors that occur behind closed doors. Who knows what we could learn if we started treating domestic violence with the gravity it deserves.