1) China is known to have contributed[0] to bat coronavirus research, my speculation is that Wuhan’s BSL-4 lab exists primarily for this reason.
2) There were documented lab escapes of original SARS-CoV from labs in Beijing[1] in 2004, as I recall resulting in at least one death.
3) WHO’s study starts this month, but they don’t seem to mention lab escape (not of some “engineered virus”, just straight up a natural sample escaping on a person) as a possibility[2]. I am not sure if they are playing politics or this is their sincere outlook.
I can’t stress this enough: China may have been unlucky to be struck by the original SARS-CoV, so it’s reasonable that they had the motivation to study its origins; that research is valuable and it’d be absolutely bonkers to criticize scientists for having done it. Even if lab escape did indeed happen to be the cause of SARS-CoV-2 pandemic, I am not sure this should be a basis for prosecution of a particular country (as opposed to e.g. tightening of BSL security practices): there’s human factor, and mistakes happen; if it hadn’t been China it could’ve eventually been another country.
What I find alarming is if an effort to obstruct the study of pandemic origins in order to save face (?) is taking place. If it was a lab escape, humanity’s future could be much safer if we knew how it happened—but how would researchers know it was a lab escape if they can’t look in that direction?
[0] https://virologyj.biomedcentral.com/articles/10.1186/s12985-... (2015, two authors are with Wuhan Institute of Virology)
[1] https://en.wikipedia.org/wiki/2002–2004_SARS_outbreak#April_...
[2] https://www.who.int/publications/m/item/who-convened-global-...