The statement should be assumed false until proven to be true by the accuser. A negative, public claim with zero evidence (nor even a promise of forthcoming evidence) should be viewed as defamatory.
>If the statements Amazon made are false, then they are clearly defamatory, since they accuse the employee of criminal action.
Here's a key piece. If Amazon is now claiming that their former employee took criminal actions:
1) Amazon took criminal actions.
2) Why reveal this now, instead of taking it to the proper authorities when it was discovered?
>Do you really believe that Amazon's expensive lawyers didn't vet this post before it went out?
Does it matter? Expensive does not mean they are competent, nor does it mean they are correct.