please consult an attorney. Provide him or her with copies of the trust, account statements, etc. for review. Who was the other trustee and why wasn't that trustee watching the accounts?
What about the other co-trustee? You should retain counsel to sue your mother and hopefully recover from her personally.
This is not legal advice nor intended to create an attorney-client relationship. The information provided here is informational in nature only. This attorney may not be licensed in the jurisdiction which you have a question about so the answer could be only general in nature. Visit Steve Zelinger's website: http://www.stevenzelinger.com/
You have the choices of filing a civil lawsuit and/or making it a criminal matter.
You should have an attorney guide you in the timing of these matters.
The answer given does not imply that an attorney-client relationship has been established and your best course of action is to have legal representation in this matter.
Was a bond required? Was the other trustee involved? How long ago did all of this happen? Without delay, you should consult with an attorney to review the trust and listen to your story. Do it ASAP