Legal Question in Wills and Trusts in California

The trust document should be looked at first, but self dealing is probably the number one reason for removing a trustee.

You don't provide enough information to be sure, but that probably is perfect grounds to replace her.

I agree that you need to provide more facts. First, is the trust irrevocable at this point? Or are the Settlors still alive (even though your sister is the trustee)? If the trust is irrevocable, then you should have received a copy of the trust instrument and also at least annual accountings. If you have not been provided with an accounting recently, then you should request one. While it sounds like a classic scenario to seek removal, any attorney would need to review both the trust and the accountings to provide more specific advice. I would be happy to discuss this with you further.

That does sound like grounds for removal. I suggest you take the trust instrument and any other relevant documents and speak to an attorney that handles trust litigation.