Roof, who is accused of killing nine people at a black church in Charleston, South Carolina, in June 2015, was deemed competent to stand trial last week
Jury selection had been under way when US District Judge Richard Mark Gergel halted the process to allow Roof to undergo a competency evaluation. Gergel ruled Roof was competent, but he sealed a document containing the reasons for his finding. Disclosing the document would jeopardize Roof's right to a fair trial, the judge said.
The process of selecting a jury of Roof's peers resumed Monday.
Federal court officials said 20 jurors were questioned during the deliberation, seven of those were found to be qualified and 13 jurors were excused. The court will continue questioning jurors until 70 qualified jurors are identified.
At least one possible juror was asked if a person should face the death penalty for taking another life. The judge eliminated one juror who answered the question by saying the punishment should fit the crime. Prosecutors and Roof agreed to the judge's move.
Another juror was pressed on the matter after saying in her questionnaire, "I'm Catholic, and I'm not sure I could decide on the death penalty."
She told the judge during Monday's hearing that she had not followed the case so it was difficult for her to say what she would do theoretically. It would depend on "the facts on hand," she said, before concluding she could not impose capital punishment.
Gergel struck her without objection.
Another juror was cut from the pool without objection after expressing opposition to imprisoning people for life without parole, because of the cost, while expressing support for the death penalty in murder cases.
The judge also asked jurors if Roof's race or the race of the victims would affect their ability to be impartial.
One potential juror said in a questionnaire that she was sickened by the thought of someone killing people in a church. The judge asked if this would affect her ability to be impartial and later ruled that she be nixed as a potential juror.
Potential jurors are being asked to leave the courtroom if prosecutors or Roof state concerns about their qualifications. Roof, who had legal representation sitting with him in the courtroom, has not yet issued any objections.
Roof faces 33 federal charges: nine counts of violating the Hate Crime Act resulting in death; three counts of violating the Hate Crime Act involving an attempt to kill; nine counts of obstruction of exercise of religion resulting in death; three counts of obstruction of exercise of religion involving an attempt to kill and use of a dangerous weapon; and nine counts of use of a firearm to commit murder during and in relation to a crime of violence.
If convicted, he could face the death penalty.
Roof also faces nine counts of murder and other charges in the state court system. His trial in that case is scheduled to start in January.
The trial resumes at 9 a.m. on Tuesday when 24 prospective jurors are expected to be questioned.