That "makes me think it might have been someone who works here," he said.
The Navy Yard has three gates, according to its website. One is open around the clock and must be used by visitors. A second gate is only for military and civilian Defense Department employees. The third gate is for bus traffic.
The Navy Yard is part of a fast-growing neighborhood on the banks of the Anacostia River in southeast Washington, blocks from the Nationals Park baseball stadium.