(WASHINGTON) — Investigators believe hackers working on behalf of China’s main intelligence agency are responsible for a massive data breach involving the theft of personal information from as many as 500 million guests of the Marriott hotel chain, a U.S. official said Tuesday. Investigators suspect the hackers were working on behalf of the Chinese Ministry of State Security, an official briefed on the investigation told The Associated Press. The official, who was not authorized to discuss the matter publicly and spoke to the AP on condition of anonymity, said investigators were particularly concerned about the data breach in part because Marriott is frequently used by the military and government agencies. Marriott, which announced the data breach on Nov.