Could I be counter-sued for initiating a police investigation into the accounting practices of my sibling presiding over my mothers estate?

My sister was doing the monthly billing for my mother who just recently past from pancreatic cancer. I do know she was NOT and authorized signature on my mothers checking/savings account. But she did have access to these accounts as well as her social security checks. There has been some questionable spending for my sisters benefit and I have no way to verify the accounting. I was the original admin of her POA and will for 12 years. My older sister found out and had a new POA/Will drafted about 1 week before my moms death. In my opinion, she was not of sound mind/body at that time due to the amount of morphine she was on due to stage 4 cancer. It is my belief she did this to keep me from looking into my mothers accounts. There was no probate as my sister cashed out her checking/savings accounts in order to avoid paying taxes on it. There is some more background but can be discussed if someone were to call me. Thank you.