The circumstantial evidence is that the initial outbreak was concentrated in a wildlife market in Wuhan, on the opposite side of the city from the lab. The SARS

The circumstantial evidence is that the initial outbreak was concentrated in a wildlife market in Wuhan, on the opposite side of the city from the lab. The SARS outbreak began in a nearly identical way, in a wildlife market in a large city, 1000 km away from where the bats live. There's no evidence that the lab had this virus previously, and there's actually good evidence that they didn't have it (they publish on the viruses they discover, and they never published this virus).