"I expect we'll hear that a grand jury is issuing subpoenas soon..."
I don't understand this. Why is a grand jury needed? I would think the DOJ would just need to file charges and go to trial.
I believe the Seventh Amendment of the U.S. Constitution requires an indictment from a grand jury.
The sequence is investigate, indict, bring to trial, convict. This situation is just beginning to develop. Federal indictments are possible only thru a grand jury in other jurisdictions an indictment can come from a judge as well.