Question

I work for a government entity. Someone who was previously my supervisor, but no longer is, has continually harrassed me with petty things to the point I seriously consider filing a Hostile Work Environment grievance against her with my HR department. Here's the latest test to my patience, I recently found out she's been reading my emails. She is not my supervisor, my supervisor was not aware of this nor did he authorize it, she simply abused her position as being in a "supervisory" postion over the IT department. She had the IT Manager give her access. Do I have any recourse or expectation of privacy in regards to her unapproved behavior? It would be one thing should my supervisor or HR have approved it or if there was any provocation or display by me of potential illegal or illecit behavior. Thanks