First of all: the criminal part is prosecuted by the state, so you don't have to worry about it, and you can't.
Secondly: the rest is civil litigation. You need to do this yourself, keep the materials well, and then sort out your civil lawsuit according to the criminal punishment after the criminal part is tried.
It is said that more than 2000 people have been cheated, so you'd better organize a class action lawsuit. Intermediary responsibility depends on the result of criminal trial.
1, if the middleman also bears criminal responsibility, then he will bear great civil responsibility.
2. If the middleman is also a victim, there is almost no responsibility if there is no illegal income.