Federal prosecutors in South Carolina want to know what mitigating factors the defense plans to present during the sentencing phase of the death penalty trial of accused Charleston church shooter Dylann Roof.

Prosecutors said in court documents filed Monday such disclosure before the trial was ordered in the Boston Marathon bombing case. Prosecutors say providing the information beforehand will allow the government to investigate defense claims and help seat an impartial jury.

Mitigating circumstances such as drug abuse or mental illness relied on in sentencing are generally not required to be revealed until after a defendant is found guilty.

But the government wants the judge to order the defense to reveal such factors by Oct. 1. The 22-year-old Roof stands trial Nov. 7 in the slayings of nine parishioners at Emanuel AME Church.