A Defense Department analyst and a former engineer for Boeing Co. were charged Monday in separate spy cases for allegedly handing over US military secrets to the Chinese government, the Justice Department said. Additionally, two immigrants from China and Taiwan accused of working with the defense analyst were arrested after an FBI raid Monday morning on a New Orleans home where one of them lived. The two cases - based in a Washington suburb and Los Angeles - have no connection, and investigators said it was merely a coincidence that charges would be brought against both on the same day. The arrests mark China's latest attempts to gain top secret information about US military systems and sales, said Assistant Attorney General Kenneth Wainstein. He described China as "particularly adept, and particularly determined and methodical in their espionage efforts."