Mr. van der Zwaan originally told Mr. Mueller's investigators that he had not spoken to Mr. Gates since August 2016, but subsequently admitted he had lied after prosecutors confronted him with evidence of conversations. "In any event, a sentence that ensured van der Zwaan's return to the United Kingdom for the birth of his child in August 2018 would be within the recommended Guidelines' range".
Gates pleaded guilty to conspiracy and making a false statement in February and is cooperating with Mueller's probe.
Federal Bureau of Investigation agents, working with Mueller's office, "assess that Person A has ties to a Russian intelligence service and had such ties in 2016", according to the filing.
Van Der Zwaan faces a sentence of zero to six months, but asked for a non-jail sentence since his willingness to admit his false statements and correct the record "has come at great cost".
A new filing from special counsel Robert Mueller's team released Tuesday night alleges that Rick Gates communicated with a former Russian intelligence officer while he was working for the Trump campaign in the 2016 election.
But Van Der Zwaan said he was motivated to lie to hide conversations he recorded with Gates and someone identified only as Person A. Gates had contacted Van Der Zwaan, according to the filing, in 2016 instructing him to contact Person A, who told him the new Ukrainian government might file charges against Van Der Zwaan and other Skadden lawyers with whom he worked on the Tymoshenko report.
For those keeping score, van der Zwaan is the son-in-law of a Russian oligarch, German Khan, one of the owners of Alfa Bank, and had extensive dealings with Manafort on his earlier work for the Yanukovych regime in Ukraine. In a sentencing memorandum federal prosecutors filed late Tuesday, they even told the judge that the Department of Justice "does not take a position with respect to a particular sentence to be imposed".More news: NCAA Tournament: Kansas holds off Clemson; Villanova victorious
Van der Zwaan was part of a team that worked in 2012 on behalf of the Ukrainian government on a report about the trial of Yulia Tymoshenko, the former Ukrainian prime minister.
Both Mr. Manafort and Mr. Gates were indicted a year ago for money laundering and other financial crimes committed while, the charges said, they tried to hide the money they received for their Ukraine work.
Van der Zwaan, the son-in-law of a Ukrainian-Russian oligarch, was sacked a year ago from the law firm Skadden, Arps, Slate, Meagher & Flom, according to the firm, after it says it learned of his alleged crime from the special counsel's team. Given the "unusual and unnerving" conversations, van der Zwaan secretly recorded them, his lawyers wrote, and he feared that revealing the communications to the special counsel's office could lead to the discovery of the recordings.
Tuesday's filing from Mueller's office says it was "pertinent to the investigation" that "Gates and Person A were directly communicating in September and October 2016".
The special counsel's office described the calls in its court papers as "memorable".
That Person A has had ties to Russian intelligence is not terribly surprising. He also revealed that before getting involved with Manafort and Gates in 2005, he worked for the International Republican Institute, a US-funded "democracy promotion" outfit whose board of directors is now chaired by Senator John McCain (R-Arizona).
Van der Zwaan then made a decision to "correct the record", and went back for another meeting with the special counsel's office on December 1. "And while his actions following his initial meeting with the [special counsel's office] can not absolve him from culpability, they are compelling mitigating factors in considering punishment".