COLUMBIA, S.C. - Lawyers for Dylann Roof want to delay picking a jury in his federal death penalty trial because of the publicity surrounding the mistrial in a former police officer's case.

Roof's lawyers filed the request Tuesday. Jury selection is expected to start Wednesday in Charleston, where a mistrial was declared earlier this week for former North Charleston police officer Michael Slager.

Roof's attorneys say if U.S. District Judge Richard Gergel goes forward, he at least needs to question the jury pool extensively about their opinions in the Slager case.

Race plays a central role in both cases. Slager, who is white, shot and killed a fleeing, unarmed black driver.

Roof is charged with killing nine people at an African-American church in June 2015