Two enormous challenges:
Obtaining all evidence needed to guarantee court verdict in a way that makes it impossible to challenge, even with the best lawyers (which they will certainly have)
Protect whistleblowers and other potential witnesses who will be critical to prosecution. I hope to God they are all very well hidden and protected.
Starting to wonder how many years this will be in court.
The only possible way to avoid a legal backlog that could last until after every single person involved has died is with military tribunals.