My dad passed away last week. Need access to footage

My dad passed away last week unexpectedly in a car accident. In the 4 days that it took me to fly across the country his ex wife gained access to his house via her daughter that had been staying there-and several really important things disappeared. He has several ring camera’s including ones inside. How do I go about gaining access to that footage for evidence. His phone is password locked and my ex step sister won’t give me the login info. I suspect she is attempting to delete evidence. I have a death certificate… but no paperwork saying that I’m the administrator of the estate. I am going through the legal channels for that right now. I’m pretty sure she stole his will and destroyed it, because she has come up with an old will and is attempting to take over his estate. Help please