A key D.C. councilwoman expressed concern Wednesday about a new executive order from Mayor Adrian Fenty that appears to grant Police Chief Cathy Lanier broad authority to issue subpoenas. The order, signed quietly by Fenty last month and posted on the city’s Web site last week, gives the chief the power to probe “any municipal matter” and allows Lanier to delegate her subpoena power “to her subordinates.” Councilwoman Mary Cheh, D-Ward 3, a constitutional law professor and former prosecutor, wrote a letter Wednesday to Fenty, asking him to explain the order. “I have grave concerns over the prospect that this...