I would strongly advise you to hire an attorney. No offense, your current methods of trying to collect have not worked thus far. My firm offers free case consultations in these matters and handles these matters. Our office number is 813-830-2261. Good luck.
This answer does not, nor is it intended to, create an attorney-client relationship or constitute attorney advertising. Rather, it is offered solely for informational purposes. The facts of each case are different and unique, it is critical to consult with qualified counsel with whom information can be shared and assessed under attorney-client privilege, so that competent and quality advice can be obtained on which you can make informed decisions
Contact an attorney. Even though he declared bankruptcy, the odds are that he did not disclose the debt owed to you. As a result, it constitutes undisclosed debt that was not discharged in the bankruptcy. Beyond that, if the money was supposed to be invested in a business, and that business is still a going concern with assets, that should give you more options.
The big question here will be collecting. If you win a judgment against him, will you be able to collect it.
Please feel free to give my office a call. I frequently handle cases like this.
My response to this question is a response to a hypothetical situation based on limited facts. I am not your attorney; you are not my client and we do not have an attorney-client relationship. If you need a lawyer, you should contact one in your area. If you would like to talk with me about your case, you can call my office.