St. Louis Police officers guard the entrance to the Cathedral Basilica before Midnight Mass as protesters held a candlelight vigil on Wednesday, Dec. 24, 2014, in St. Louis. The mayor of the St. Louis suburb of Berkeley urged calm Wednesday after a white police officer killed black 18-year-old Antonio Martin who police said pointed a gun at him, reigniting tensions that have lingered since the death of Michael Brown in neighboring Ferguson. AP Photo/St. Louis Post-Dispatch, Robert Cohen