First, you have to establish that it was a total breakdown which I think you will have a hard time establishing in any meaningful way. But by all means. Let's hear the argument.
The Boss says I can not trust this person again nor can their coworkers for x y z reasons (And I Am afraid Mr Danmore has done this) and the employee is toast.
This is a civil matter so its on the balance of probabilities this isn't a criminal court.