The location of the release says little about who done it.
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Maybe.
But there is video evidence of a Chinese official bragging that it WAS a bioweapon and a first strike on America.
The Chinese zero-Covid policy seems consistent with a belief that it was a bioweapon since the policy puts in place the testing, contact tracing, quarantining, and other social organization measures that would be needed to counter a future biological weapon attack using an agent for which the Chinese have no vaccines or drugs.
That is, they are responding to it as though it is a hostile “first strike”.