There are two indicators, one simply how close it was to a virus lab doing similar studies, and two how immediately and blindly people denied that they could be

There are two indicators, one simply how close it was to a virus lab doing similar studies, and two how immediately and blindly people denied that they could be any connection. They'd have had to investigate before making a claim, and had not, so obviously they're lying. A concerted conspiracy to deny an option is some evidence for that option being true. I don't claim it did come from a lab, but that anyone stating categorically that it did not is lying.