They might have burnt the reputation built for this particular pseudonym but what is stopping them from doing it again? They were clearly in it for the long run.
Anyways, yes it is an interesting question whether he/she is alone or they are a group. Conway's law probably applies here as well. And my hunch in general is that these criminal mad minds operate individually / alone. Maybe they are hired by an agency but I don't count that as a group effort.