The chair of the WHO (Tedros Adhanom) [1] was a communist rebel (Ethiopian People's Revolutionary Democratic Front) fighter in north africa and his career has been sponsored and guided by China for this reason.
They won't suppress findings made internally because it would be too hard to cover up - but they will 'do the least' with respect to finding answers.
Only the US has enough power and wherewithal to even try to do something, but they'll be kept out direct, so it boils down to how sophisticated the US clandestine efforts are in China.
My completely speculative guess is that US operating ability in China is 'really bad' and that they've already barked up that tree and found nothing conclusive.