I think if more up to date evidence or evidence that negates that previously given is used to acquit people previouly found guilty - as in the George Davis case - then by the same token it should also be possible to re-try someone previously found innocent. It has been accepted for many years that better forensics and better systems can cast doubt on any prior case. Whether the defendant was found guilty or innocent should be irrelevent and such newer evidence should be able to overturn any prior ruling. Just my 2 penn'urth.

DtG