2. Is highlighting out things that he has shared publicly going to potentially help a criminal case against him?
IANAL, but was once a juror on a case that was decided based on something the accused admitted in his testimony. The prosecuting attorney hadn't noticed it, but some jurors did, and it was the fact that allowed us to reach a unanimous decision.
So, yes, I can easily imagine that you might have picked up on something that would otherwise go unnoticed by those prosecuting a criminal case.
Is your goal to help the hundreds of frum yidden who lost thousands of dollars, so you want to provide information that would help their criminal case?
Or is your goal to hinder the criminal case, to help one frum yid avoid jail?
If the first, your information should go directly to those affected. If the second, keep mum.