There are advocacy groups that can help you if the District Attorney's are unwilling to help you.
You should speak with an attorney as soon as possible and adhere to their advice.
To be blunt the answer is that there is no one overseeing these issues. Each DA's office is independent and does there own review. There are advocacy groups but none that have any oversight of any particular DA's office.
The advice I have given does not bind the parties in any manner and is merely given as a courtesy.
Texas Code of Criminal Procedure Article 20.09 says that "The grand jury shall inquire into all offenses liable to indictment of which any member may have knowledge, or of which they shall be informed by the attorney representing the State, or any other credible person."
What this means is you can hire an attorney to go before the grand jury, just make sure you hire someone with experience in doing so.
Pamela Fernandez's response to your question is for general information purposes only. Nothing in this response should be taken as legal advice for any individual case or situation. This information is not intended to create, and receipt or viewing does not constitute, an attorney-client relationship.