Sen. Tom Cotton (R-AR) on Sunday once again amplified a debunked conspiracy theory about the origin of the coronavirus outbreak. Scientists believe it started with an animal-to-human transmission at a market in Wuhan, China. But appearing on Fox News, the Republican senator noted that China has a lab nearby that researches human pathogens, The Washington Post noted. “Now, we don’t have evidence that this disease originated there, but because of China’s duplicity and dishonesty from the beginning, we need to at least ask the question to see what the evidence says,” Cotton said. Numerous experts have already said the coronavirus—which has so far caused the most damage inside China—is not a man-made bioweapon. But conspiracy theorists continue to flog that scenario. That includes Cotton, who had noted the close proximity of the lab and on Twitter before Sunday.

Later on Sunday, Cotton doubled-down, saying his comments didn’t reflect a conspiracy theory but a “hypothesis.”