Well, to be frank we do not know if the "witness" acted in good faith or not, although the actions of Plod suggest it might be otherwise.
Let the wheels of Justice grind.
Sadly, this is an illustration of what at first seems to be a worthy use of "Social Media" turning out instead to be a distraction. People naturally rush to judgement, with the very best of intentions, but care needs to be taken to contribute in measured fashion to a proper process.