Story highlights Dylann Roof is accused of killing nine people at a church in 2015

State of South Carolina is also set to try Roof and will also seek death penalty

(CNN) Federal prosecutors will seek the death penalty for Dylann Roof, who is accused of killing nine people at a historic African-American church in Charleston, South Carolina, in July 2015.

Roof, who is white, is charged with 33 federal offenses, including hate crime charges for allegedly targeting his victims on the basis of their race and religion. A judge entered a not guilty plea on his behalf in July 2015.

"The nature of the alleged crime and the resulting harm compelled this decision," Attorney General Loretta Lynch said.

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Roof, 22, is accused of shooting participants of a Bible study class at Emanuel African Methodist Episcopal Church, known as Mother Emanuel, in downtown Charleston on June 17, 2015.

Among the victims was the church's pastor, the Rev. Clementa Pinckney, who also was a state senator.

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