There was singing at this morning's service, which was held inside a sports arena at the College of Charleston. The arena was also the site of the funeral for the late Rev. Clementa Pinckney, one of the nine people killed in the shooting.
President Obama gave the eulogy at Pinckney's funeral and led the thousands of attendees in a rendition of "Amazing Grace."
That musical interlude was one of the many emotional moments that took place in the aftermath of the shooting.
Roof, 22, is awaiting his federal trial which is slated for November and faces a possible death penalty sentence. The Associated Press reports that his defense attorneys have said that he is willing to plead guilty if the prospect of the death penalty is dropped.