A string of fires at predominantly black churches in the South have fueled concerns about the potential for a new wave of racist violence in the days since a white gunman killed nine black worshippers in Charleston, South Carolina, NBC News reported. Federal authorities, including the FBI and the Bureau of Alcohol, Tobacco, Firearms and Explosives, have joined local authorities looking into fires in Georgia, North Carolina and South Carolina. In each case, the church was severely damaged or destroyed — with congregations left wondering if they were specifically targeted by bigots. FBI data shows a sharp decline in bias-motivated torchings of black churches in the past two decades, though members of some churches in the South aren't convinced. "I'm suspicious," said Angulis Williams, the deacon at Glover Grove Baptist Church in rural Warrenville, South Carolina. His small church, with 35 active members, was gutted by fire before dawn on Friday.