What if case "A" remains sealed until a key defendant who has entered into a (sealed) plea deal has finished testifying against defendants in other separately filed (and sealed) indictments (cases B,C,D,E,F,G, etc)?
The purpose of sealing would be to prevent the targets/defendants in the other sealed indictments from learning that a sealed indictment has been filed against the additional targets.
Then if one person in each of the next later of indictments is secretly arrested and agrees to flip (plea deal for cooperation), that leads to another layer of targets, another layer of sealed indictments…
Repeat and Repeat.
If the ultimate target is 15 layers away, or 35 layers away, none of the underlying indictments can be unsealed without tipping off the top targets.
Only those down at the bottom, who don't have any testimony that leads far enough up the indictment chains could be unsealed.
Take a look at the sealed indictments in Project Gunrunner…. Op Wide Receiver I sealed, led to Op Wide Receiver II sealed, led to Fast & Furious sealed. Wide sweep of arrests. Other related cases, low level cartel guy case, sealed until testimony in court. Another case sealed until arrests effected, with deniability in place that it was related.
From my perspective, that is what makes the current number of remaining unsealed indictments so extraordinary. A huge spider web of connections, where earlier ones can't be unsealed without pulling on a thread of the web that alerts so many others.
Although at this point, the rumors have to have leaked out.
Arrests in one huge nationwide swoop?
Shock and Awe?