Elder abuse by a caretaker. How do I go about reporting such a complex situation?

My grandparent's caretaker has been using fear tactics to have them agree to extremely damaging acts against me ever since I raised suspicion that money and narcotics they said went missing all conveniently went missing when their caretaker was around. He's only been in their lives for 2 years and things have consistently gone missing the entire time he's around, with breaks when he's not. He's accused me of being on drugs, abusing them, and quitting my job all in an attempt to discredit me. How do I go about reporting such a complex situation?