Peg, i think your perspective is right on target ! it's all about coordination of the facts on a timeline basis. and Mueller's team has been very effective discovering and connecting the dots. enough so that Michael Cohen confessed only hours after Manafort was sentenced.
I believe Mueller has had them for a while and needed a Trump Organization insider to corroborate what has been suspected for a long time - then along came Allen Weisselberg who was granted immunity for talking.
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