Roof, a self-avowed white supremicist is on trial for the cold-blooded murders of nine people of the Emanuel AME Church last year.
The judge denied the defense's motion.
"He's evil. There is no place on earth for him except the pit of hell," said Ms. Sanders.
The defense quoted those words in the motion for mistrial but before he denied the motion, U.S. District Judge Richard Gergel said that he interpreted Ms. Sanders' comment as a religious statement, not as a recommendation for sentencing.
Roof has so far shown no outward emotion during testimony but family members, some jury members and court officials wiped away tears as Ms. Sanders described how she held her 11-year-old granddaughter against her chest to keep her quiet during the shooting and watched the scum fatally shoot her 26-year-old son while he tried to persuade Roof to stop the attack.
The prosecution called police investigators to the stand to discuss the forensic evidence from the massacre, and the judge warned the court that the testimony and evidence will be graphic.
The current jury panel of 12 jurors and 6 alternatives. Among the 18 panelists, 12 are white, 5 are black, one panelist is unspecified. Thirteen are female and 5 are male. Of those 18 individuals, it will not be known which panelists will serve as alternatives until the end of the trial.