A business litigator.
Sadly, this is not uncommon behavior, and the law is pretty well established regarding breach of fiduciary duty, conversion (civil theft), the right to an "accounting", the right to force the holding of meetings and depending on the facts, many more causes of action.
You will need to assemble all the documents you have in your possession when you see the lawyer. You should reduce all the background and "facts" to writing to help the lawyer. If you have specific goals or issues, it will be clearer if they are reduced to writing.
The above is general legal and business analysis. It is not "legal advice" but analysis, and different lawyers may analyse this matter differently, especially if there are additional facts not reflected in the question. I am not your attorney until retained by a written retainer agreement signed by both of us. I am only licensed in California. See also avvo.com terms and conditions item 9, incorporated as if it was reprinted here.