White supremacist Dylann Roof on Monday stood by his pledge not to testify or call any witnesses who might persuade jurors not to sentence him to death for killing nine black parishioners at a church in Charleston, South Carolina, in June 2015.

That leaves jurors deciding his fate to consider only the evidence offered by U.S. prosecutors, including four days of poignant testimony from more than 20 family and friends of the victims, who recounted the lives of their loved ones, ages 26 to 87, and the impact of their deaths.

Roof is representing himself. The jury last month found him guilty of 33 counts of federal hate crimes resulting in death, obstruction of religion and firearms charges for the massacre during a Bible study meeting at the historic Emanuel African Methodist Episcopal Church.

Deliberations about whether Roof should be put to death or sent to prison for life were scheduled to begin on Tuesday.

U.S. District Judge Richard Gergel denied Roof's request that the judge decide his sentence rather than the jury.

Earlier Monday, federal prosecutors rested their case in the penalty phase after several family members spoke about Tywanza Sanders, 26, who according to trial testimony told the gunman, "You don't have to do this" before he was shot at least five times.

Sanders was ambitious, determined and headstrong, his sister, Shirrene Goss, said.

"He was not fearful to try anything and not fearful to say what was on his mind," she said.

At the time of his death, the college graduate - who was the youngest of the victims, had been preparing to move to Florida to study audio engineering, said his mother, Felicia Sanders, one of three survivors of the shooting.

"The hardest thing was when (the school) called to say 'Where's Tywanza Sanders? He didn't show up at class,'" his mother told jurors. "And my husband had to say 'He died, he can't come, he's no longer with us.'"

Roof did not ask questions of witnesses. He seldom objected to the government's evidence detailing his premeditation and lack of remorse, including a racist manifesto written from his jail cell after his arrest.

He told jurors in an opening statement last week that he was serving as his own lawyer to prevent their hearing details about his mental health.

The lawyers who represented him during the trial's guilt phase said Roof's strategy proved he was not fit to represent himself. However, Gergel twice ruled Roof competent.