only remaining anonymous because I promised before the conversation expecting some type of business deal
You have no responsibility to someone trying to commit fraud. If I tell you to promise to keep a secret, and then reveal to you that my secret is that I am a lifetime conman or a serial killer, you do not have a responsibility to keep my secret.
On the contrary, you have a responsibility to let people know who is attempting this fraud, so that people may protect themselves from this scum. He's likely conning unwitting people in the Bitcoin Marketplace right now.
I don't know. They didn't actually do it but expressed their interest in doing it. I honestly don't know what to think. Part of me would feel guilty when I agreed to speak candidly the other part tells me to say something to protect others. But even then they would just change username anyways, so would it actually help? Hmmm.....I need time and help to think this one through... I DO NOT like breaking my word!