Who is Ma Zhongyan from Dragon Bones: A Novel and what is their importance?

Ma Zhongyan is in charge of the Site 518 excavation. Educated in the United States, Ma is well versed in both American and Chinese culture. Ma enjoys receiving what he believes are bribes from the museum curators who seek the treasures being found at the site, and he constantly teases the staff, but he is unhelpful and resentful to Hulan and David. Over time, it is revealed that Ma does not work for the Cultural Relics Bureau, but rather, is employed by the Ministry of State Security, China's version of the CIA.