 The commanding officer of 4th Marines, then Colonel John C. Beaumont, was one of only two people in China, the other being the naval attaché in Beijing, Commander Thomas M. Shock, to know the actual mission William A. Worton was undertaking for the Office of Naval Intelligence in attempting to penetrate Japan with agents from China.Worton, who had served as a Marine in China 1922—1926, 1927–1929, and 1931–1935 and been commended for his intelligence work by General Butler during Butler's 1927–1929 command of the 4th, arrived during the summer of 1935 to recruit and run agents until his turn over and return to the United States in June 1936.The peaceful years ended 7 July 1937 when Japanese incursions resulted in an incident at the Marco Polo Bridge used by Japan to send more troops into China.