You need to contact a local business litigator immediately. Depending on the facts, there may be claims of breach of fiduciary duty, breach of contract, trade secret claims, so on.
Get an attorney. Contact people you know and trust for referrals. If you have no referrals review this site or contact your local bar referral program. Good luck.
DISCLAIMER—This answer is for informational purposes only and discusses general legal principles, trends, and considerations and is not intended as specific legal advice regarding your question. This answer does not establish an attorney client relationship.
While I do not practice in Texas, and can only answer based on California law, there might be a claim for interfereing with your contracts or business relationsips with your existing customers or suppliers.
As my esteemed colleague noited in a previous response, you should contact an attorney in your area quickly, before any damage can be done.
PLEASE NOTE THAT THIS RESPONSE SHOULD NOT BE CONSTRUED AS A LEGAL OPINION OR ADVISE, AND DOES NOT CREATE AN ATTORNEY-CLIENT RELATIONSHIP. IN ORDER TO RENDER A LEGAL OPINION OR ADVISE, THE RESPONDING ATTORNEY WOULD NEED FAR MORE INFORMATION THAN HAS BEEN PROVIDED, AND WOULD NEED TO BE RETAINED PURSUANT TO A WRITTEN FEE AGREEMENT.
While I am not licensed in Texas, your issues is one that is generally governed by legal principals that are similar in most states. I agree with my colleagues and would add that in Illinois you may also have a claim of tortious interference with business relationships as well as a breach of fiduciary duties and the other claims my colleagues have mentioned. So I too would recommend you contact a business litigator as soon as possible to discuss your matter and possibly seek injunctive relief against your business partner and his investor.
This answer is for informational purposes only and is not intended to be legal advice nor does it establish an attorney-client relationship. Please consult a local business/litigation lawyer to obtain legal advice that is tailored to your circumstances and facts. Good luck to you.