"Did not see evidence of tampering" is too weak to trust for me.
Military-funded scientific biowarfare research should be different (use different, more advanced, tools) than run-of-the-mill bioinformatics research which US scientists work with. So if the scientist is not working on military research, their guess is as good as: "it was not engineered using common industry-standard known methods". It is misattributing authority, like quoting bio science experts saying "COVID can't be a weapon because the mortality is too low". No, you have zero idea about the military applications of biowarfare. If the scientist really was a military researcher, then they won't disclose signs of tampering to a news outlet or academic journal.
Another is that, for obvious reasons, military research would like to obfuscate its engineering. So it is unlikely they use easily detectable methods for that. It is perfectly possible to breed viruses in a lab, inside natural hosts. Then you won't see any biological markers of tampering, but the virus was still engineered by cross-breeding captured fruit bats or manually creating a zoonotic transmission chain to humans. So even without biological signs of tampering, the lab leak remains plausible.
Military-funded scientific biowarfare research should be different (use different, more advanced, tools) than run-of-the-mill bioinformatics research which US scientists work with. So if the scientist is not working on military research, their guess is as good as: "it was not engineered using common industry-standard known methods". It is misattributing authority, like quoting bio science experts saying "COVID can't be a weapon because the mortality is too low". No, you have zero idea about the military applications of biowarfare. If the scientist really was a military researcher, then they won't disclose signs of tampering to a news outlet or academic journal.
Another is that, for obvious reasons, military research would like to obfuscate its engineering. So it is unlikely they use easily detectable methods for that. It is perfectly possible to breed viruses in a lab, inside natural hosts. Then you won't see any biological markers of tampering, but the virus was still engineered by cross-breeding captured fruit bats or manually creating a zoonotic transmission chain to humans. So even without biological signs of tampering, the lab leak remains plausible.