Story highlights Sentencing phase is scheduled to begin on Wednesday

Dylann Roof was convicted of all 33 charges on December 15

(CNN) A federal judge ruled Monday that Dylann Roof, convicted of killing nine people inside an African-American church in Charleston, South Carolina, is mentally competent to represent himself at the sentencing phase of his trial.

That phase is scheduled to begin Wednesday morning at 9:30. Roof could be sentenced to death.

Roof was evaluated over the weekend by Dr. James Ballenger of Charleston, a specialist in forensic psychiatry, with the results presented in court.

US District Judge Richard Gergel closed that part of the proceeding to the public, saying he wanted to protect Roof's right to a fair trial and right to self-representation.

Ballenger evaluated Roof in November, before Roof was found competent after a two-day hearing, Gergel's order said. But the court "felt that the serious nature of the proceedings" against Roof indicated the need for another evaluation by the court-appointed Ballenger "to confirm there were no material changes in his mental status" since then.