In a court document filed Monday, authorities said they intended to call experts to outline how Roof’s comments, writing and the media he consumed “are consistent with the adoption of a white supremacy extremist ideology, including a belief in the need to use violence to achieve white supremacy.”
Prosecutors said Roof’s “self-learning process” led him to adopt the thinking “that violent action is necessary to fight for white people and achieve white supremacy … and that the choice of targets and execution of violent action should be conducted in a manner that promotes these objectives, to include publicizing the reasons for those actions to inspire others to engage in violent action to further white supremacy.”
In addition, federal authorities said they had found two handwritten manifestos and a list of churches — and that one of these manifestos was found in Roof’s jail cell.
Attorneys for Roof declined to comment on the new filing.
The Southern Poverty Law Center said in a report earlier this year that the Internet is an ideal venue for “lone wolves” like Roof. “White supremacists are increasingly opting to operate mainly online, where the danger of public exposure and embarrassment is far lower, where younger people tend to gather, and where it requires virtually no effort or cost to join in the conversation,” the report stated.
After the church attack, officials found a manifesto online belonging to Roof that was filled with racist characterizations of black people and others. On this site, which one official said was modified hours before the shooting, there were also images of Roof holding a Confederate battle flag, burning an American flag and standing in front of a Confederate history museum.
One of the new manifestos was found in Roof’s jail cell, while the other was found in his car, authorities said.
In the filing, prosecutors also said that evidence suggests that Roof’s sentiments grew in the months before the attacks. During this period, Roof traveled to the Emanuel AME Church, as well as areas connected to the Confederacy, according to the filing, submitted by the office of Beth Drake, the acting U.S. attorney for the District of South Carolina.
Prosecutors seeking a federal death sentence have said that the shooting was carefully planned and racially motivated. They said that Roof targeted the church’s Bible study group to “magnify the societal impact” of the rampage and that “his animosity towards African Americans played a role in the murders.”
Earlier this month, attorneys for Roof filed a motion to challenge the death penalty, arguing that capital punishment “constitutes an unconstitutional punishment.” In this motion, Roof’s attorneys said that if the Justice Department changed its mind about seeking a death sentence, their client would plead guilty to the federal charges and agree to be sentenced to life in prison without parole.
Also on Monday, Drake’s office filed a response to this challenge, asking a judge to reject that motion questioning the death penalty itself.
This story, first published at 4:35 p.m., has been updated.