This photo provided by Charleston County Sheriff's Office shows Dylann Roof, Thursday, June 18, 2015. Roof, 21, was arrested Thursday in the slayings of several people Wednesday, including the pastor, at a prayer meeting inside The Emanuel African Methodist Episcopal Church in Charleston, S.C. (Charleston County Sheriff's Office via AP)

White gunman caught in killing of 9 in historic black church

It was an act of “pure, pure concentrated evil,” Charleston’s mayor said — a black community’s leading lights extinguished in a spray of bul…