How to find out about an estate

My sister is the administrator of my fathers estate. I believe that she has done some shady stuff with everything. I know for a fact that our father had a business before he died and it was lucrative and she just took the business over. It should be in the estate and not just given to her without us getting anything for it. I am trying to find out if she filed the correct tax returns for both the estate and my father personally but I can't get the EIN number for the estate because the IRS says I am not her. Is there another way to get that number so I can inquire about the returns? I know for a fact she didn't file the correct inheritance returns for PA. She is also an accountant so for her to not do things correctly could be tax fraud and her license taken away. The estate has been open for 9 years still.