FJ owns all the documents we mentioned above, including the IDs and a selfie of the account associated with the case. However, we don't have the legal right to publish it publicly without particular notice from the official entities or from the user himself agreeing to the fact of us doing it so.

There is another problem here as well. If both IDs don't belong to the OP and he bought them somewhere, he might not have a problem to ask you to prove what you are saying and make that data public or send it to a forum admin/ trusted user. After all, the documents are not his, and he wouldn't care about who sees them. What are you going to do if he does exactly that and asks to have someone take a look at your proof? Chances are, you could be sharing someone else's IDs that got stolen/hacked from that individual.