Something that had been merely suggested before has now been blown wide into the open in China.

A spokesman for China’s foreign ministry, Zhao Lijian, tweeted yesterday that “it might be the US army” that brought the coronavirus to China, giving an official boost to a conspiracy theory that had been allowed to circulate on Chinese social media for weeks. The conspiracy posits that 300 athletes from the US military who in October attended the 7th Military World Games in Wuhan, where the epidemic first broke out, were infected with the virus, thereby spreading it in China.

Zhao’s comment accompanied a video from a US congressional hearing this week on the country’s response to the epidemic. Robert Redfield, director of the US Centers for Disease Control and Prevention (CDC), said in the video that some patients who were previously diagnosed to have died from the flu were found to have actually died from the coronavirus. The video began trending on Chinese social network Weibo, with many commenting that they now believe firmly that the US had covered up facts related to the epidemic.