Population Research Institute President Steven W. Mosher wrote at the New York Post on Saturday that China’s coronavirus epidemic could have been unleashed by researchers who sold laboratory animals to the notorious “wet markets” of Wuhan for extra cash.

Mosher is not the first skeptic of Beijing’s official coronavirus narrative to note the presence of an advanced microbiology lab near Wuhan, the city where the epidemic originated. Since the early days of the crisis, theories have suggested everything from the lab accidentally releasing the virus to speculation that the virus might have been deliberately designed as a biological weapon.

His theory cited as evidence the release of new guidelines from the Chinese Ministry of Science and Technology calling for “strengthening biosecurity management in microbiology labs that handle advanced viruses like the novel coronavirus.”