Dylann Storm Roof, the white supremacist who is charged with shooting and killing nine black people at a black church in Charleston, S.C., last week, took offense to the fact that a love interest preferred a black guy over him, The Intercept reports.

Roof’s cousin, Scott Roof, told The Intercept in a phone interview that the 21-year-old man was “normal” until “he started listening to that white power music stuff.” Scott added that Dylann “kind of went over the edge when a girl he liked starting dating a black guy two years back.”

It’s not the first time a white mass killer got pissed because white women he liked preferred black guys. Before Elliot Rodger killed six people in California on May 23 of last year, he wrote in his manifesto: “How could an inferior, ugly black boy be able to get a white girl and not me,” Rodger wrote. “I am beautiful, and I am half white myself. I am descended from British aristocracy. He is descended from slaves. I deserve it more.”

Scott told Intercept’s Juan Thompson that “Dylann liked her. The black guy got her. He changed. I don’t know if we would be here if not …”

Scott hung up.

The cousin’s description of Dylann’s hate for interracial relationships are consistent with reports that he told the victims he killed that they were “raping our women” and “taking over our country.”

Keep in mind that, as Slate’s Jamelle Bouie wrote, racists have a long history of using the myth of black sexual predation to justify violence:

This fear took its most violent form in the years after the Civil War—when blacks won their freedom—but it’s been with us for centuries. Throughout the antebellum period, whites lived in terror of a challenge to the racial order and believed that black freedom would lead to a world of “Negro domination” where they lived as slaves, or worse. Likewise, during the 1864 election, Northern Democrats attacked Abraham Lincoln as a “black Republican” who sought to debase the white race with miscegenation. Similar accusations were used during the civil rights movement, and in the North, urban whites justified residential segregation—in patterns that still exist—as necessary protection from the violent, sexually aggressive black criminal.

So, Dylann Storm Roof would just be one of many thin-skinned racists who used the fear of interracial relationships between black men and white women to justify his white supremacist violence.

He has been charged with nine counts of first-degree murder.