U.S. Sen. Barbara Mikulski said Thursday that she and other members of Maryland’s congressional delegation support Baltimore’s mayor in asking for a broad federal investigation of whether city police engage in discriminatory patterns or practices—a request sparked by the death of Freddie Gray, a black man who suffered a fatal spinal injury in police custody last month. The Democratic senator told U.S. Attorney General Loretta Lynch during a Senate subcommittee hearing that Lynch would get a letter later Thursday from the Maryland delegation supporting Mayor Stephanie Rawlings-Blake’s request, made Wednesday. “In many cities throughout the country, including my own city...