Roger Stone, a key ally of Donald Trump, has been arrested on charges of obstruction, witness tampering and making false statements.
The office of the special counsel, Robert Mueller, announced his arrest on Friday.
Mr Mueller is investigating Russia’s interference in the 2016 US election and any ties to Mr Trump’s campaign.
Mueller’s inquiry alleges that Mr Stone made multiple attempts to contact WikiLeaks through an intermediary about documents stolen from the Democratic national committee and Hillary Clinton’s presidential campaign.
He was also said to have passed on information to Trump’s election campaign team about the documents.
Stone was arrested in Fort Lauderdale, Florida, on Friday after an indictment was issued by a federal grand jury in Washington DC the day before.
Stone would appear in court in Fort Lauderdale later on Friday.
Mueller’s indictment alleges that during the summer of 2016 Stone spoke to senior Trump campaign officials about WikiLeaks “and information it might have had that would be damaging to the [Hillary] Clinton campaign. Stone was contacted by senior Trump campaign officials to inquire about future releases by” WikiLeaks, which the document refers to as “Organization 1.”
“On multiple occasions, Stone told senior Trump campaign officials about materials possessed by Organization 1 and the timing of future releases,” the document states.
Stone did not hold an official position in Trump campaign organisation. However, he is the president’s longest serving informal political adviser.
It was Stone who first recommended that Trump’s team hire as its campaign manager, Paul Manafort, who has been found guilty on eight counts of financial crimes.
