https://www.who.int/health-topics/coronavirus/origins-of-the...
Origins of the SARS-CoV-2 virus
And unlike the arrticle here, this report is based upon interviews with employees at the lab and various form of documentation provided by the lab. Including health records of the employees.
For more from one of the WHO people:
https://theconversation.com/i-was-the-australian-doctor-on-t...
I was the Australian doctor on the WHO’s COVID-19 mission to China. Here’s what we found about the origins of the coronavirus
> We visited the Wuhan Institute of Virology, which is an impressive research facility, and looks to be run well, with due regard to staff health. We spoke to the scientists there. We heard that scientists’ blood samples, which are routinely taken and stored, were tested for signs they had been infected. No evidence of antibodies to the coronavirus was found. We looked at their biosecurity audits. No evidence.
So this is what they were told, but did they actually test the samples, and confirm that they belonged to the right people and originated from the given date? Apparently no.
> We looked at the closest virus to SARS-CoV-2 they were working on — the virus RaTG13 — which had been detected in caves in southern China where some miners had died seven years previously. But all the scientists had was a genetic sequence for this virus. They hadn’t managed to grow it in culture.
This is probably the most convincing argument: if they actually had worked on viruses similar enough to plausible be modified into SARS-CoV-2, this would have left evidence in scientific papers etc.
> While viruses certainly do escape from laboratories, this is rare. So, we concluded it was extremely unlikely this had happened in Wuhan.
This is incredibly weak: "lab escapes are rare, so it's extremely unlikely" is not much of an argument.