I agree with JB's questions. In the instant situation, Ms. Mullin was transferred/promoted and accepted a severance package for leaving her old job. This severance pay was offered and accepted. If something was wrong with it, it was in the offering and shoddy methods of justification for it. So far nothing has come out to pin that part on her.

She did inflate her resume quite substantially, particularly pertaining to said prior job. Could that be the reason for firing her? Misrepresentations on applications are often grounds for immediate dismissal.

The hints and allegations regarding her past have come up because of the investigation into the severance, and cast doubts on her integrity which somehow was not in question before. So, maybe they fired her because they no longer trust her, and therefore feel she is not able to do the job for which they hired her. That flies in the face of the judicial system, since she has not been charged with anything, but it does go to the usual hiring method of checking references for reputation. If a reference raises a question, the hiring entity will usually pass on that applicant absent any overwhelmingly positive factors.