“i used to be mutuals with someone who is now a real school shooter ;-).” —post on an X (formerly Twitter) account believed to belong to Solomon Henderson
Natalie Rupnow, the fifteen-year-old who opened fire in December on her fellow students and teachers at Abundant Life Christian School in Madison, Wisconsin, killing two people before taking her own life, didn’t fit the loner white male school shooter stereotype. In the gruesome history of U.S. mass school shootings, she was perhaps the first female perpetrator in forty-five years.
However, Rupnow was like other modern extremist youth in at least one way: She was extremely online. Her extensive digital footprint across multiple social media platforms showed obsessive interest in gun culture, school shooters, and neo-Nazis. Any reasonable adult who bothered to look at Rupnow’s social media profiles before she committed a mass shooting would have been appalled by what they found, and concerned for her safety and well-being. And anyone who dug deeper would have seen that Rupnow wasn’t merely fangirling. She was engaging in online communities that celebrated violent acts, glorified those who perpetrated them, exchanged so-called best practices, and encouraged one another to commit shootings and other acts of terror.
Two of Rupnow’s online relationships in particular have received a lot of media attention. Alexander Paffendorf, a twenty-year-old man in Carlsbad, California, was detained by the FBI three days after the shooting in Wisconsin, and accused of plotting a parallel attack with Rupnow. According to Carlsbad police, Paffendorf admitted to law enforcement that he’d “told Rupnow that he would arm himself with explosives and a gun and that he would target a government building.” A judge issued a protective order, and Paffendorf was forced to surrender his arsenal. (As of publication, he has not been charged with any crime.)
Rupnow was also in communication with another future mass shooter, Solomon Henderson. Per reporting by Wisconsin Watch and ProPublica, Henderson and Rupnow were both active in the same online communities that promoted mass shootings and glorified violence through memes, terrorist propaganda such as manifestos, and sharing tips for committing similar crimes. While there’s no evidence that they plotted their attacks together, they were in contact and egging one another on.
Moments before Rupnow opened fire at her school, she posted a white supremacist gesture on her X account—perhaps a signal that her attack was underway. A user that researchers now believe to be Henderson immediately replied with, “Livestream it.” After news of the Madison shooting broke, Henderson celebrated Rupnow and their friendship, bragging on X that “i used to be mutuals with someone who is now a real school shooter ;-).”
Weeks later, in January, Henderson opened fire in the cafeteria of Antioch High School in Nashville, Tennessee, where he was a student, killing another student before taking his own life.
“I started browsing 4chan in May 2020 after extreme boredom, remember this was during the outbreak of covid.” —Payton Gendron on how he found extremism
Solomon Henderson, who was Black, also doesn’t fit into the school shooter mold. Henderson left an extensive online history that offers chilling insights into his own indoctrination, including a manifesto and a diary. Marc-André Argentino, an expert on violent extremism and radicalization, analyzed both Henderson’s manifesto and diary and found “evidence in [Henderson’s] writing of elaborate scheduling for high-casualty events, possible bomb deployments, tracking of personal purchases for improvised explosives, and the repeated invocation of past mass shooters as role models to act as a source of motivation. The overall portrait is of a young individual consumed by self-hatred, hostility toward multiple demographic groups, and a drive to achieve infamy through catastrophic violence.”
Argentino found Henderson was on multiple online platforms, from closed communities to X and Bluesky. Henderson would encourage others (including Rupnow) to commit school shootings and share tips and tricks on how to carry out attacks with other would-be shooters. Henderson was a cheerleader for violence, and people who committed violent acts of terror.
Henderson’s writings also show extreme self-hatred. In his diary, he made frequent racist comments toward himself. He also struggled with his body image, notably his height. Argentino’s analysis suggests that this self-hatred fed into Henderson’s “broader sense of failure and bitterness toward society.” Eventually, Henderson’s racial hatred extended to other racial groups as well.
The more I learned about Henderson, the more I noticed the resemblance between Henderson’s writing and the manifesto and diary of another recent mass shooter, Payton Gendron. Gendron, who murdered ten people at a grocery store in Buffalo, New York, in 2022, used his manifesto to promote the so-called Great Replacement—a false conspiracy theory that is prominent in both rightwing online communities and mainstream political discourse of the American right. Extremist manifestos often involve a lot of material that is copied and pasted from other manifestos and far-right writings, and a full 80 percent of Gendron’s appears to have been lifted from other sources. In just two years, he had absorbed a lot from his online peers. “I started browsing 4chan in May 2020 after extreme boredom, remember this was during the outbreak of covid,” he posted in his manifesto.
Mass shooters being radicalized online is nothing new, but the communities, archives, and materials that exist online—as well as the ways people are finding one another and encouraging one another to commit violent acts—is a troubling evolution that cannot be ignored. Henderson’s diary includes a listing of every mass shooter terrorist and how many people each one killed. He frequently referenced other attacks and attackers in his writings.
Henderson’s online footprint likely made me think of Gendron because Henderson admired Gendron’s crimes, particularly the way he livestreamed his attack. In his analysis, Argentino notes that Henderson’s online diary is reminiscent of the one kept by Gendron.
There’s a term for this kind of activity that encourages terrorism and violence: networked incitement. It was coined by Joan Donovan, assistant professor of journalism and emerging media studies at Boston University and a longtime researcher of online extremist movements, who defines it as involving “insurgents communicating across multiple platforms to command and coordinate mobilized social movements in the moment of action.”
Donovan tells me that radicalization has changed since the COVID-19 pandemic, when the primary social outlet for a generation of young people across the globe moved online for a lengthy period: “Young folks are radicalizing themselves through access to online message boards and chat groups.”
“The lone wolf narrative doesn’t work anymore,” she continues. “There are communities now. People are now finding each other online to do crimes.”
Donovan explains that the primary audience has also changed. Young people, radicalized online, are seeking to impress their Internet friends by committing acts of violent terror and living in infamy as a mass shooting meme in those same communities. “The core set of people they’re seeking to impress are in that community now,” Donovan says. “Becoming the meme of a school shooter requires procuring arms, carrying out a violent attack, and creating a network of watchers who will pay attention.”
Natalie Rupnow admired some figures on Henderson’s list who had committed mass shootings and acts of violence and terror. Violent criminals are these shooters’ heroes, and the way to become like their heroes is to commit more acts of terror. Online communities and platforms offer encouragement and support every step of the way as young people become radicalized. The forums’ continued existence assures would-be terrorists that their acts will live on and they, like the violent criminals they admire, will be lionized and canonized in these online spaces; that their mutual followers will become fans who spread the word about their acts of terror and inspire the next wave of mass shooters and terrorists.
“He sought many things from his act of terror, but one was notoriety—that is why you will never hear me mention his name.” —Jacinda Ardern, former prime minister of New Zealand
I’ve been researching and writing about mass shootings and school shootings for nearly a decade. It’s always a challenge to inform people of the dangers of online radicalization without amplifying the existence of these online spaces and potentially drawing more attention to them. I don’t want to amplify Henderson, Rupnow, or anyone who commits violent acts of terror, nor do I want to contribute to mythologizing them and their crimes. But it’s crucial that we understand what’s happening in these communities and what can be done to stop radicalization.
As a parent, I also struggle with the reality that this is a systemic issue that families are left to deal with mainly on their own without much structural support. Gun culture continues to dominate in the United States, and despite broad public approval, Congress has shown again and again that it is unable and unwilling to pass reasonable gun safety reforms. The tech platforms where these communities form, grow, and recruit have rolled back their policies on hate speech and gutted trust and safety teams via layoffs. In the case of X, the platform has become a far-right paradise where hate speech has surged and is often shared by Elon Musk, the company’s current owner and the most amplified person on X.
There’s an infamous headline from The Onion, the satirical news site, that goes viral after every mass shooting: “ ‘No Way To Prevent This,’ Says Only Nation Where This Regularly Happens.” The outlet reposts the article again and again because the United States continues to stand alone in our complete inability to protect ourselves and our children from the terror of mass shootings.
Meanwhile, consider what happened in New Zealand after the Christchurch mass shooting in 2019. The government under then Prime Minister Jacinda Ardern passed gun control legislation and tackled online hate by taking on the tech platforms, the country’s largest Internet service provider, and making it impossible to access the extremist online message board 8chan. Local media outlets collectively agreed not to amplify white supremacist rhetoric in their coverage of the eventual trial. They followed the lead of Ardern, who vowed never to say the shooter’s name.
Still, Americans aren’t giving up, and are looking for creative ways to curb radicalization and violence. Victims of the Buffalo shooting and their families are suing tech platforms including Facebook, Reddit, and YouTube in an attempt to hold them liable for radicalizing the shooter. In Michigan, the parents of a school shooter were charged with crimes and found guilty in 2024 for failing to prevent their son from committing his violent crimes. These actions in the courts will hopefully set a precedent for prosecutors and the families of other victims to follow, creating at least some cost, accountability, and friction.
However, it’s mostly left to us—families, schools, and local communities—to keep young people from the extremism pipeline and to prevent them from committing violent crimes. This includes encouraging our children to be safe online and not allowing the Internet as a primary means of socialization. It also includes vigilance about what young people are consuming online and where they’re congregating. Thankfully, there are some resources available for parents, educators, and coaches—anyone on the front lines who engages with young people on a daily basis. The Polarization & Extremism Research & Innovation Lab at American University, in partnership with the Southern Poverty Law Center (SPLC), has produced guides for parents and caregivers, educators, coaches, and community leaders to help identify the signs of radicalization and offer strategies for engaging young people before it’s too late.
Donovan also offers parents and caregivers advice: “Be alert for when your kid prefers isolation and solitude rather than being with friends and outside. Asking your kids about current events and their views will also help clue you in if they have extremist views.” She also recommends checking to see if your children are on messaging platforms like Discord or Telegram and knowing who they’re talking to on those platforms.
What I keep coming back to, as a researcher and a parent, is how these online conversations exist in plain sight for anyone who cares to find them. Much of the conversation is happening on mainstream platforms, in a public forum. Henderson and Rupnow were interacting on X in the lead-up to Rupnow’s shooting. It strikes me that for both of these teenagers, an intervention might have gone a long way, perhaps preventing their radicalization and the deaths of their victims.
I’m also struck by how neither one fit the profile of a school shooter, and how both were radicalized into communities centered on racism and misogyny. If Rupnow and Henderson can be indoctrinated by communities that hate them, any young person is vulnerable. It is urgent that we understand this and work to counteract it, as more and more people go down a rabbit hole that grows wider by the day.