ARLINGTON, Va. — An admiral says workers will start returning in February to the Washington Navy Yard building were 12 were fatally shot last year.Vice Adm. William Hilarides (hill-AHR'-ih-dees) told defense contractors at a breakfast meeting Thursday in Arlington, Virginia, that he expects all 2,700 to be back in Building 197 by the end of April. The building will be renamed for Joshua Humphreys, designer of the first Navy frigates.Hilarides runs Naval Sea Systems Command, the Navy's shipbuilding agency. Headquarters workers relocated to other buildings in the Washington area after the Sept. 16 shootings. Gunman Aaron Alexis, a civilian contractor, was killed by police in a shootout.The admiral says he's proud of the workers' resilience. But he says some suffer from post-traumatic stress from the violence they witnessed.