WASHINGTON After a year of Donald Trump s complaints that a criminal investigation into his presidential campaign is nothing more than a witch hunt, it turns out that special counsel Robert Mueller may have, in fact, found a Russian witch.

In the final months before the 2016 election, top Trump campaign aide Rick Gates was in contact with a former member of Russian military intelligence whose background he knew about, according to a new court filing by Muellers office.

Federal Bureau of Investigation Special Agents assisting the Special Counsels Office assess that Person A has ties to a Russian intelligence service and had such ties in 2016, states a sentencing memo in the case of Alex van der Zwaan, a Dutch lawyer who pleaded guilty to lying to federal prosecutors earlier this year.

The White House press office did not respond to HuffPost queries about the memo in light of Trumps repeated questioning of the legitimacy of Muellers investigation. Press secretary Sarah Huckabee Sanders did offer the standard White House blanket denial that Trump or his campaign had done anything wrong.

There was no collusion and were confident in that, Sanders said.

Trump has called Muellers probe a hoax and a witch hunt dozens of times since taking office 14 months ago. Of late, he has taken to writing witch hunt in all capital letters for emphasis.

The Mueller probe should never have been started in that there was no collusion and there was no crime. It was based on fraudulent activities and a Fake Dossier paid for by Crooked Hillary and the DNC, and improperly used in FISA COURT for surveillance of my campaign. WITCH HUNT! he tweeted on March 17.

Two days later, he tweeted , A total WITCH HUNT with massive conflicts of interest!

The new document, filed late Tuesday, is the most recent tidbit to emerge from Muellers closely guarded investigation, which so far has produced five guilty pleas and indictments of 14 others including 13 Russians who worked to help elect Trump as well as the former chairman of Trumps campaign, Paul Manafort.

Gates was Trumps deputy campaign chairman and later the campaigns liaison to the Republican National Committee.

Manafort and Gates were also business partners in efforts to help pro-Russian politicians in Ukraine, and their indictments accused them of money laundering in that work. Gates has pleaded guilty and is cooperating with Mueller, while Manafort has vowed to fight the charges.

Person A is not identified in the court filing, but the description reportedly appears to match Konstantin Kilimnik , who managed a Kiev lobbying office for Gates and Manafort.

Last summer, according to The New York Times , John Dowd, who was then the presidents main personal lawyer on the Mueller investigation, discussed the idea of giving pardons to Manafort and to retired Army Lt. Gen. Michael Flynn, Trumps first national security adviser. Flynn has also pleaded guilty in the Russia probe, for making false statements to investigators. Pardons could make it harder for Mueller to gather evidence against Trump personally but could make it easier for Mueller to prove obstruction of justice.

Dowd denied the pardon story in a brief phone interview with HuffPost on Wednesday. I didnt have discussions, he said, before hanging up.

At Wednesdays press briefing, Sanders referred all questions about any pardon discussions to a statement from Ty Cobb, the lawyer handling the Mueller probe for the White House. His statement also denied that there had been any talk of pardons.

The U.S. intelligence community concluded during the 2016 campaign that not only was Russia interfering in the U.S. election, but it was actively trying to help Trump and hurt Democratic nominee Hillary Clinton.

The FBI began its probe of possible collusion between the Trump campaign and the Russians well before Election Day. Control of the investigation was shifted to Mueller after Trump fired then-FBI Director James Comey in May 2017. Soon after, the president told NBC News as well as senior Russian officials visiting the Oval Office that he had done so because of the investigation.