“You have vandalized my heart, raped my soul and torched my conscience,” the 23-year old Virginia Tech gunman, Cho Seung-Hui declared before killing 33 people on campus, including himself. “You thought it was one pathetic boy’s life you were extinguishing. Thanks to you, I die like Jesus Christ to inspire generations of the weak and the defenseless people.”

We need to listen to Cho’s words and heed his concerns as he eerily echoes those of previous school shooters outraged at what they perceived as an unjust school hierarchy that used them as the pariahs to reinforce their own social status and power. Yet in this tragedy, as in past school shootings, authorities ignore the shooters’ own explanations for their crimes, instead labeling the horror as merely an aberration. The mental illness that may well have plagued Cho is only a piece of a story. As we mourn the victims of the terror Cho wrought at Virginia Tech, we need also to ask how the bullying he experienced may have pushed him over the edge.

Contrary to the views of experts like Former Homeland Security Director, Tom Ridge, who said Cho was just “deranged,” peers of many of the perpetrators of past similar crimes concede that those young men were bullied relentlessly. “Luke was picked on for as long as I can remember,” explained a classmate of sixteen-year-old Luke Woodham, who killed his ex-girlfriend and her best friend and injured seven others in the 1997 school shooting in Pearl, Mississippi. “I do this on behalf of all kids who have been mistreated,” Luke also declared.

While their reactions were heinous and reprehensible, these are not random, unprovoked acts of violence but rather a common grievance among many American students. Most react more quietly with suicide, depression, anxiety, truancy, and other more self-destructive responses.

Bullying instigated over 40 school shootings that took place during the past decade. Cho, like the other shooters, had difficulty with girls (stalking two who reported him to the police, speaking often of an “imaginary girlfriend,” and making many uncomfortable by taking photos of their legs in classes). Like the other perpetrators, he was relentlessly bullied and angry at what he perceived as an unjust school hierarchy that privileges the wealthy. Cho was also bullied as a result of his race: “Go back to China” his peers said to him on one of the rare times he mustered up the courage to speak in class.

This dynamic was also in play at Columbine High School, which until Virginia Tech was the most infamous school shooting. Eric Harris and Dylan Klebold, age 17 and 18, also did not meet the narrow social expectations expected of them at school. They said they were treated like dirt by fellow students and declared their unwillingness to accept the bullying that seemed to have become a socially acceptable and daily form of violence: “Your children who have ridiculed me, who have chosen not to accept me, who have treated me like I am not worth their time are dead....” railed Eric.

In every school shooting, boys targeted girls who rejected them, boys who called them gay or otherwise belittled them, and other students at the top of the school’s hierarchy—white, wealthy, and athletic—and then shot down other students in an effort to reinstate their injured masculinity.

In 1997 in West Paducah, Kentucky, 14-year-old Michael Carneal killed three girls, two of whom had rejected him. The following year, in Jonesboro, Arkansas, 13-year-old Mitchell Johnson and 11-year-old Andrew Golden shot their ex-girlfriends as well as two other girls who refused Mitchell’s advances. Mitchell “vowed to kill all the girls who broke up with him” and threatened other girls for even speaking about these rejections. His ex-girlfriend complained that Mitchell was stalking her and had even hit her, but no one responded to her concerns. In Edinboro, Pennsylvania, that same year, 14-year-old Andrew Wurst targeted his ex-girlfriend at a school dance. He threatened her prior to the shooting when she first broke up with him. “Then I’ll have to kill you,” he said. At Columbine, Dylan and Eric were known to have big problems with girls. Dylan was so shy with girls that his parents paid him $250 to attend the Columbine High School Prom.

Boys are taught to believe that sexual interest from a girl is imperative to affirm their manhood. When boys are rejected by girls, it can bring up fears that they are not perceived by others as strong and powerful and can cause many to doubt their masculinity and heterosexuality. Headlines about Cho confirmed he struggled with these same concerns about his manhood.

Cho also raged against the rich, declaring his shooting a response to the “brats” and “snobs” at his school who were not satisfied with their “gold necklaces” and “Mercedes.” Cho, whose parents ran a dry cleaner, seemed to believe that the relentless bullying he experienced was a result of his lower economic status and his race.

In high schools as well as colleges, popular kids tend to be wealthier and the boys at the top of school caste are often perceived as “jocks.” Those that don’t fit into these categories are often teased, or seen as relatively unimportant or even invisible. The boys who killed generally came from less wealthy backgrounds than those they targeted and almost all of them specifically aimed at those perceived as wealthy and popular: the “jocks and preps” in the school who were also the ones who bullied them. Like Luke, Michael, and Eric & Dylan and many others, sixteen-year old Evan Ramsey, who killed two students and injured two others in Alaska in 1997, had been picked on by popular football players, whom he targeted in his shooting after an argument with one of them.

Classmates at Columbine High School described how the jocks teased Eric and Dylan. “Everyone would make fun of them” said Ben Oakley from the soccer team. And senior Dustin Thurmon, from the Columbine wrestling team repeated what many others expected: “They should have been able to take it.”

But children in our schools should not have to take it. Repeatedly, teachers, parents, and other adults and students say that bullying is a normal part of school life, a rite of passage, or simply a case of “boys will be boys” and sometimes “girls will be girls.” Yet my research has traced bullying as a cause of almost every school shooting to date and other research shows that bullying can lead to suicide, severe depression and anxiety, truancy, and dropping-out of school. We need to find a way to stop bullying in schools and to refute assumptions that this behavior is normal.

Many shooters blamed adults for not protecting them from daily assaults. Eric Harris continued: “Teachers, parents, let this massacre be on your shoulders until the day you die.” He echoed Evan’s words who said after his shooting: “I figured since the principal and the dean weren’t doing anything that was making any impression, that I was gonna have to do something, or else I was gonna keep on getting picked on.”

These shootings are not just aberrations of deranged individuals. They are a reprehensible and unconscionable retaliation to common and real pain felt by students across our nation. Those who solely blame mental illness miss the real concerns about bullying these boys raise, troubles sadly shared by between 25 and 80% of students, according to various studies. We need to examine the persistently cruel school social hierarchies that so many young boys have declared the source of their unbearable misery. Time and again these boys beg for help from adults who either ignore the bullying or impose “zero tolerance” policies—suspending students for any hint of impending violence— that tend to punish minor infractions which often miss the big picture. Our students must feel more supported and accepted by one another independent of race, class, and success with the opposite sex. Stalking was an issue in many of the school shooting cases, as well as sexual harassment, dating violence, and gay-bashing—some of which were issues at Virginia Tech. These concerns must be taken seriously and never written off as “normal bullying.”

Now we flip-flop between ignoring bullying altogether, considering it “normal” and implementing “zero tolerance” policies that don’t address the relationships among students and between students and adults. We need instead to create communities in schools and raise awareness of all parties involved including victims, bullies, and bystanders so that school hierarchies are dismantled and students treat each other with sincere appreciation and respect. European countries have implemented such community-oriented programs with national policies that already reduced bullying by fifty percent. The Netherlands launched such a program in over 10,000 schools that spread like wildfire through Europe. Here we are still using zero tolerance with zero evidence that any of it is working. We have no national policies and only scattered efforts that try to improve relationships between students and among students and adults. If we don’t listen to the terrifying words sung repeatedly by each school shooter, we are sadly likely to see many more such horrors.