Mueller also demonstrated that he can tap at will into other federal law enforcement branches and their deep bench of experienced investigators when he needs specific kinds of help.

One has been Michael Welch, an IRS special agent whose has spent 25 years leading investigations into tax cheats. Two others are FBI forensic accountant Morgan Magionos and Paula Liss, a Treasury Department expert in fraud and money laundering. Both testified in the Virginia trial about how the Mueller team relied on their expertise to sift through millions of dollars in payments from secret foreign bank accounts.

The FBI is anchoring Mueller’s probe in other vital ways too. About 14 agents raided Manafort’s Alexandria, Virginia, condominium last summer to procure the financial documents and emails so central to the government charges. Special agents also went to the homes of bank executives who did business with Manafort for interviews. One of the contractors who did millions of dollars of work on Manafort’s homes described during last month’s trial meeting “for several hours with a very pleasant young lady from the FBI who went step by step, invoice by invoice, over detail of each invoice, matching it with each payment.”