CHARLESTON, SC - JUNE 26:  President Barack Obama sings 'Amazing Grace' as he delivers the eulogy for South Carolina state senator and Rev. Clementa Pinckney during Pinckney's funeral service June 26, 2015 in Charleston, South Carolina. Suspected shooter Dylann Roof, 21, is accused of killing nine people on June 17th during a prayer meeting in the church, which is one of the nation's oldest black churches in Charleston.  (Photo by Joe Raedle/Getty Images)