Our nation — still grieving the recent Las Vegas tragedy — now mourns the lives lost in this week’s massacre by a gunman who opened fire in a church in Sutherland Springs, Texas, leaving a death toll of 25 and an unborn child.

As was the case with the Pulse nightclub massacre in Orlando, Florida, the San Bernardino Elementary School shooting, the open fire on congressional members playing baseball, and, according to Everytown USA, a majority of other recent mass shootings, the gunman had a history of domestic violence that should have raised red flags. The Texas church shooter, specifically, had served a year in military jail for beating and choking his wife, threatening her with a firearm, and fracturing her child’s skull, and was not eligible to have a gun.

Through our grief, we search for answers and long to prevent further tragedy. Part of our agony is that so many of these massacres are preventable. As a co-chairwoman of the county review team that examines local domestic violence fatalities and makes recommendations to prevent further deaths, I am painfully aware of how domestic violence endangers homes, schools and communities and of how our nation needs to engage in better violence prevention efforts, starting with our youth.

It’s one thing to look back through the histories of men like Devin Kelley and pluck out the red flags; it’s another to intervene early enough to interrupt the interlinked misogyny, violence and firearm possession that often underlie their crimes.

Only in recent years have we realized the early age at which relationship violence begins. A 2011 report from the Centers for Disease Control and Prevention reveals that many girls as young as 11 experience dating violence.

During teenage years, according to a report from the National Council on Crime and Delinquency, one in three girls in the United States experience dating violence, with consequences including elevated rates of suicidal thoughts and actions, substance abuse, sexually transmitted infections, teen pregnancy, future experiences of domestic violence, and fatality.

Preventing relationship violence at an early age is crucial because, as Duke University professor Jeffrey Swanson told CNN, “a history of violent behavior is a far better predictor of future violence than mental illness.”

Regarding the causes, empirical research explains that relationship violence is about power and control: Abusive partners engage in violence and coercively controlling behaviors to gain and maintain power and control over an intimate partner. Research also reveals that gender inequality, patriarchy (or male control in domestic or intimate settings), and intergenerational patterns perpetuate abuse.

Children’s peer relationships contribute to and predict violence in their adult relationships as well; for example, a study of familial and peer influences found that male youth who have friends with “aggressive attitudes toward women” are at increased risk of becoming perpetrators of domestic violence. Studies have also found links between firearm possession and male gender, dating or intimate partner violence, and substance abuse.

Positively, anti-violence programs that target youth ages 11 to 14 are the most effective at preventing domestic violence because relationship expectations are being set during this highly formative period.

In my work, I frequently engage in these educational efforts and witness results firsthand. For example, residents I worked with in a juvenile detention center told me that before our program on teen dating violence, they didn’t know they had a right not to be hit and didn’t know they could end a relationship, all of which demonstrates the pressing need for early education and intervention.

Programs such as Dating Matters and Safe Dates offer training programs and best practices for educators and other adults to help teens establish healthy and safe dating norms and promote respectful behavior.

While Kelley’s horrific record of domestic abuse and animal cruelty reflects his behavior as an adult, it doesn’t surprise me that his high school classmates reported to the Washington Post that, as they grew older, Kelley communicated increasingly inappropriately and aggressively on social media. Some of them even expressed a lack of surprise at his shooting rampage. What better argument could there be for effective intervention at a young age?

Since research shows that domestic violence prevention efforts are most effective at young ages, when seeking to prevent future gun massacres, it is equally critical to recognize the strong association between teen dating violence and firearm possession. New studies show that youth with firearms are more likely to commit dating violence, to have been in recent serious physical fights, and to endorse aggressive attitudes that increase risk for retaliatory violence. Factors such as young age, possessiveness, impulsivity, and use of force further increase the risk that young people with guns will die or kill with them.

Although individuals under age 18 are generally prohibited from possessing a handgun, surprisingly high percentages of youth possess or have access to firearms. According to the CDC, approximately one in 18 high school students in the United States report having carried a firearm in the past 30 days.

In a study of nearly 700 assault-injured youth (age 14 to 24) appearing at emergency departments, 23% reported firearm possession in the past six months, and this study excluded any firearm used for hunting, target shooting, or sporting activity. Nearly one-quarter of youth reporting firearm possession owned highly lethal rapid-fire, large-clip automatic or semiautomatic weapons.

The Texas massacre is a grave reminder that the majority of mass shootings in America are committed by individuals with histories of domestic violence. This ease of access to illegally obtained highly lethal weapons demands action, as does the connection between firearm fatalities and relationship violence.

Fortunately, there are many effective, data-driven ways to prevent gun violence supported by a majority of Americans, including gun owners and members of the National Rifle Association, such as background checks, federal databases to track gun sales, and bans on rapid-fire assault weapons, according to the Pew Research Center.

Universal background checks for all gun sales, including private sales, are supported by 83% of voters, and these background checks would, according to Everytown USA, reduce domestic violence gun murders by 47%. Naturally, for background checks to be effective, relevant data must be input in the national system maintained by the FBI. While Kelley should have been denied the sale of a firearm due to his criminal record, the Air Force had failed to provide the FBI with Kelley’s criminal history.

Because adults and youth currently easily obtain firearms outside legal channels, minimizing illegal firearm access is also key to preventing mass shootings and other gun deaths. Although some federal and state domestic violence gun laws exist, they often only cover spousal abuse, typically rely on the “honor system” for abusers to surrender guns, and obviously failed to prevent the Texas gunman from purchasing the firearms he used in this week’s church massacre. Federal lawmakers have thus far declined to enact important safety measures; to the contrary, the House recently considered legislation to increase the availability of silencers and permit concealed carry across states.

After the Texas church massacre and so many other mass shootings, legislators offer prayers and moments of silence, but are silent about meaningful reform. But prevention is possible. To avoid future tragedies, we must invest in anti-violence education beginning with our youth, pay attention to relationship violence, and enact and implement sensible gun safety measures.