The same face seems to stare at us from photographs of nearly all perpetrators of mass shootings — a morose mask with vacant eyes — daring us to ask why. Dylann Storm Roof’s is no exception.

On June 17, 2015, the 21-year-old white South Carolina man opened fire with a handgun during a Bible-study session he had been allowed to participate in at Charleston’s historic Emanuel African Methodist Episcopal Church, killing the pastor and eight parishioners, all of them black.

It was later discovered that Roof, an unemployed school dropout, loner, and alcohol and drug abuser, had his own website, which featured a racist manifesto and photos of himself posing with a handgun, a Confederate flag, a burning American flag, a jacket with Apartheid-era Rhodesian and South African flag patches, and the Nazi code number “88” (standing for “Heil Hitler”).

Roof’s actions were fraught with deliberate symbolism, and, as a result, he has become the catalyst for yet another searing public debate about racism, governmental displays of the Confederate flag, restrictions on legal gun ownership and the pervasiveness of Internet hate sites.

Yet the question remains: Would Roof have engaged in this kind of lethality even if he had not been attracted to racist ideology? In other words, was he driven by innate mental illness or by dark cultural influences?

There’s no shortage of opinions on the subject.

Roof himself clearly and publicly articulated racial animus.

“Niggers are stupid and violent,” he wrote on his website. He said he “chose Charleston because it is most historic city in my state, and at one time had the highest ratio of blacks to Whites in the country,” and justified his mission by explaining, “We have no skinheads, no real KKK, no one doing anything but talking on the internet. Well someone has to have the bravery to take it to the real world, and I guess that has to be me.”

Roof attributed his “awakening” to the Trayvon Martin case and the website of the Council of Conservative Citizens (formerly the White Citizens’ Council), a Missouri-based white supremacy group.

Yet this same young man, described by his ex-stepmother, Paige Mann, as a “sweet kid,” had black school and Facebook friends, and reportedly told police after his apprehension that he almost didn’t go through with his mission because members of the church study group had been so nice to him.

Mann believes Roof was drawn in by “Internet evil.”

An ex-FBI profiler has pegged him as a paranoid narcissist. A black childhood friend, to whom Roof confided that he wanted to shoot up a university campus, believed he was just “talking crazy” and insisted he never heard him make any racist remarks. South Carolina Gov. Nikki Haley labeled the shootings “an absolute hate crime.” President Obama spoke of the “long shadow” of slavery, Jim Crow and discrimination.

Perhaps the answer to the perennial question of nature vs. nurture is that both are probably implicated in this and other cases of gratuitous violence.

The relatively recent science of epigenetics, the study of external or environmental factors that switch genes on and off and control how they express themselves in the body’s cells, points to evidence that behavior can be influenced not only by DNA sequencing but by DNA-activating social triggers from the world in which we grow and develop.

Why and how ideologies — which provide simplistic, appealing and usually misleading answers to complex societal problems — can exert such a strong influence upon individual outlook and behavior is a phenomenon that has yet to be scientifically explained.

Though little is known about Roof’s upbringing, early reports suggest that he was mentally disturbed from adolescence. Whether racist ideology contributed toward an abnormal mental state or simply provided a vehicle to express it remains unclear.

Paige Mann, who was divorced in 2009 from Roof’s father, Franklin Bennett, claimed in a 2008 court proceeding that she was physically and emotionally abused by Bennett during their 10-year marriage, a period when Roof was growing up in their household. If true, that’s the kind of external event that can strongly imprint itself on the psyche of a child, even one who is naturally outgoing and buoyant, usually resulting in depression, anxiety and aggression.

A social milieu of hatred can also influence behavior, especially in an impressionable adolescent.

The worldview of history’s most notorious racist, Adolph Hitler, was formed when he was a young man working as an itinerant painter in the intensely anti-Semitic atmosphere of pre-World War I Vienna, fighting in the brutish trench warfare on the Western Front, and operating as an activist and rabble-rouser in the post-war political, social and economic chaos of Munich and Berlin. Yet Hitler was not born an anti-Semite. For instance, his family’s physician until 1907 was a Jewish Austrian physician, Eduard Bloch.

More recently, young Islamic men and women from respectable families have been attracted by Internet propaganda to the banner of ISIS in Syria, Iraq, Libya and Yemen, where they have participated in unspeakable acts of cruelty.

It’s easy to characterize the mayhem committed by Roof and others as pure evil, to condemn those who perpetrate it as monsters, and to strive to suppress the symbols and messages of hatred that advocate such violence.

This may be an emotionally satisfying approach but, in my view, it’s not a helpful one. Evil is a theological concept which established religions have traditionally attempted to combat, not always successfully, through exhortation and threat of divine punishment. The human psyche is too complex to pigeonhole into categories of decent people versus monsters. And the symbols and messages of hatred are so pervasive they cannot be eliminated, at least not in a free society.

Rather we have an urgent need to learn what internal and external mechanisms transform the likes of Dylann Storm Roof from a “sweet kid” into a mass murderer and figure out how best to prevent that transformation from occurring in the first place.

Elliott L. Epstein, a local attorney, is the founder of Museum L-A and author of “Lucifer’s Child,” a book about the notorious 1984 child murder of Angela Palmer. He may be reached at [email protected].