Seat a grand jury, take testimony, follow new leads where they lead. Simple enough.
Georgia Racketeering Laws … Georgia Code Title 16-14-1 - 14-4 (Georgia RICO Act)
… To bring a case under Georgia's RICO law, there must be at least two underlying felonies …
… punishable by 5 - 20 years imprisonment and/or a fine of up to $25,000 on each count …
16-2-21 — Any party to a crime who did not directly commit the crime may be indicted, tried, convicted, and punished for commission of the crime upon proof that the crime was committed and that he was a party thereto …
“Party thereto,” that could be a very long list.