But hundreds of pages of government documents — which special counsel Robert Mueller possessed since 2018 — describe Kilimnik as a “sensitive” intelligence source for the U.S. State Department who informed on Ukrainian and Russian matters.

Why Mueller’s team omitted that part of the Kilimnik narrative from its report and related court filings is not known. But the revelation of it comes as the accuracy of Mueller’s Russia conclusions face increased scrutiny.

The incomplete portrayal of Kilimnik is so important to Mueller’s overall narrative that it is raised in the opening of his report. “The FBI assesses” Kilimnik “to have ties to Russian intelligence,” Mueller’s team wrote on page 6, putting a sinister light on every contact Kilimnik had with Manafort, the former Trump campaign chairman.

What it doesn’t state is that Kilimnik was a “sensitive” intelligence source for State going back to at least 2013 while he was still working for Manafort, according to FBI and State Department memos I reviewed.

Kilimnik was not just any run-of-the-mill source, either.

He interacted with the chief political officer at the U.S. Embassy in Kiev, sometimes meeting several times a week to provide information on the Ukraine government. He relayed messages back to Ukraine’s leaders and delivered written reports to U.S. officials via emails that stretched on for thousands of words, the memos show.

The FBI knew all of this, well before the Mueller investigation concluded.

Three sources with direct knowledge of the inner workings of Mueller’s office confirmed to me that the special prosecutor’s team had all of the FBI interviews with State officials, as well as Kilimnik’s intelligence reports to the U.S. Embassy, well before they portrayed him as a Russian sympathizer tied to Moscow intelligence or charged Kilimnik with participating with Manafort in a scheme to obstruct the Russia investigation.