I respect MoA Bernhard's careful analysis of the Skripal case and his retraction today in light of the OPCW scandal:
The OPCW explained the BZ find by claiming that it had mixed BZ into the probe to test the laboratory. Something which it said it regularly does. At that time I still believed in the OPCW and found that explanation reasonable:
In light of the OPCW management manipulation or suppression of the reports of its own specialists for the purpose of attributing the Douma incident to the Syrian government I have to change my opinion. I hereby retract my earlier acceptance of the OPCW's explanation in the Skripal case.
As we now know that the OPCW management manipulates reports at will we can no longer accept the 'control probe' excuse without further explanations or evidence.
[...]My own approach to analyzing such matters is simpler: Did it happen in England? Did it have anything to do with Russia? If yes, then the British did it. How they did it makes no matter because discovery could take a half-century. This noted, of course an evidence-based approach to uncovering the truth is always preferable. But the beauty of applying my method of analysis is that one will never have to publish a retraction.