Dylann Roof has been convicted of the racially motivated killings of nine black church members in South Carolina.
The Associated Press reported how the jury managed to reach its verdict after less than two hours of deliberations.
The 22-year-old faced 33 separate charges which included hate crimes and obstruction of religion.
In addition to the nine dead, three people survived the massacre at Emanuel African Methodist Episcopal Church in Charleston in June 2015.
In their closing arguments, prosecutors said Roof was "filled with hate" while his defence said that was a suicidal loner who did not fully understand the seriousness of his actions.
During the trial, horrific images of the victims were presented from inside the church immediately after the shooting.
The jurors were shown surveillance video footage of Roof and the prosecutor Nathan Williams said: "Those people couldn't see the hatred in his heart any more than they could see the .45-caliber handgun and the eight magazines concealed around his waist." In a taped confession to FBI investigators, he is heard saying: "I did it" and "I killed them".
During the trial prosecutor Nathan Williams told the jury: "Those people couldn't see the hatred in his heart any more than they could see the .45-caliber handgun and the eight magazines concealed around his waist," The Telegraph reported.
Roof said he wanted to start a race war and chose the church because it was historically significant for the black community.
The court heard how he entered the church, was handed a Bible, and sat down in the congregation for 45 minutes before opening fire.
The jury will decide in January whether his sentence is the death penalty or life imprisonment.