Roger Stone, a longtime political advisor to President Donald Trump, was arrested during a predawn raid Friday on his Florida home in special counsel Robert Mueller's probe into election interference in 2016.
Heavily armed FBI agents swarmed Stone's property, according to CNN footage, and after a knock on the door, an agent yelled "FBI, open the door!"
Stone faces seven counts, including witness tampering, obstruction of justice and making false statements to Congress.
Stone, a veteran Republican operative who has described himself as a dirty trickster, has consistently denied collusion with Russia during the campaign. He was released on $250,000 bond after appearing at a late morning hearing at the federal courthouse in Fort Lauderdale.
"I will plead not guilty," Stone declared to a swarm of reporters outside the courthouse, where hecklers chanted "Lock him up!"
"There is no circumstance whatsoever in which I will bear false witness" against President Trump," Stone added.
The indictment alleges that Stone had been in contact with top-ranking Trump campaign officials about efforts to leak damaging information about Hillary Clinton just before the 2016 election.
According to a person with direct knowledge of the matter, the "high ranking Trump campaign official" who reached out to Stone in October 2016 was Steve Bannon, who served as CEO of the Trump campaign during the election's final stages.
Bannon's attorney declined to comment. Bannon, who worked as Trump's chief strategist in the White House for less than a year, has not returned repeated calls for comment.
Trump, in a tweet posted shortly after Stone's court hearing began, lashed out at the special counsel's investigation and the news media.
Trump was referring to the presence of a CNN's camera at Stone's house when FBI agents knocked on his door. CNN has said it was staking out several people's homes because the grand jury investigating the case had met Thursday, its usual day off.
The indictment describes repeated contacts between Stone and high-ranking members in Trump's campaign organization.
During the summer of 2016, STONE spoke to senior Trump Campaign officials about Organization 1 and information it might have had that would be damaging to the Clinton Campaign. STONE was contacted by senior Trump Campaign officials to inquire about future releases by Organization 1.
The indictment does not identify "Organization 1" or its head, but it clearly refers to WikiLeaks and Julian Assange because it says the head of the organization was at the Ecuadorian Embassy in London. Assange has been living in the embassy since 2012, initially taking refuge there while facing sexual offense allegations in Sweden. Sweden has dropped the investigation, but Assange still faces a British arrest warrant for skipping bail.
The group leaked thousands of Clinton campaign emails during the final month of the 2016 campaign. At a campaign rally in Pennsylvania on Oct. 10, 2016, Trump praised the group, saying "WikiLeaks! I love WikiLeaks." In addition, Trump's oldest son, Donald Jr., acknowledged he head been in private communications with WikiLeaks.
The indictment also says a senior official in the Trump campaign "was directed" to talk to Stone about potential future releases by Organization 1, following a release of stolen Democratic National Committee emails in July 2016:
After the July 22, 2016 release of stolen DNC emails by Organization 1, a senior Trump Campaign official was directed to contact STONE about any additional releases and what other damaging information Organization 1 had regarding the Clinton Campaign. STONE thereafter told the Trump Campaign about potential future releases of damaging material by Organization 1.
The indictment says a high-ranking Trump campaign official, whom CNBC identified as Bannon, asked Stone about whether the organization would release more material in October, with about a month left to go in the campaign. Clinton was considered the favorite to win the election at the time, leading Trump in national polls.
On or about October 4, 2016, the head of Organization 1 held a press conference but did not release any new materials pertaining to the Clinton Campaign. Shortly afterwards, STONE received an email from the high-ranking Trump Campaign official asking about the status of future releases by Organization 1. STONE answered that the head of Organization 1 had a "[s]erious security concern" but that Organization 1 would release "a load every week going forward."
The special counsel alleges that an associate of a high-ranking Trump campaign official texted Stone to praise him after an initial load of stolen Clinton campaign emails was released Oct. 7.
On or about October 7, 2016, Organization 1 released the first set of emails stolen from the Clinton Campaign chairman. Shortly after Organization 1's release, an associate of the highranking Trump Campaign official sent a text message to STONE that read "well done." In subsequent conversations with senior Trump Campaign officials, STONE claimed credit for having correctly predicted the October 7, 2016 release.
Oct. 7 also marked the release of the "Access Hollywood" tape from a decade earlier, which included Trump boasting about grabbing women's genitals. At the time, it appeared to be a mortal wound for Trump's presidential ambitions.
The indictment also says Stone
Made multiple false statements to [The House Permanent Select Committee on Intelligence] about his interactions regarding Organization 1, and falsely denied possessing records that contained evidence of these interactions; and attempted to persuade a witness to provide false testimony to and withhold pertinent information from the investigations.
Bruce Rogow, a lawyer for Stone, slammed the special counsel's office.
"I am disappointed in the grandstanding with an early morning arrest. I would have expected better from the SCO. Roger was not hiding from anyone; quite the opposite," Rogow said in a statement to CNBC. "A phone call and he would have appeared voluntarily."
Rogow also said he would work on getting Stone released from custody following his court appearance.
The White House did not respond to CNBC's request for comment. On CNN, White House press secretary Sarah Huckabee Sanders said Stone's arrest has "nothing to do with the president."
Stone, who acted as an informal advisor to Trump's presidential campaign after years of advising Trump himself, has been under scrutiny for months but has maintained his innocence. He is one of the top subjects of the investigation into potential collusion between Moscow and the Trump campaign.
Stone is also a former business associate of Paul Manafort, who headed up Trump's campaign for several months in 2016. Manafort himself has been convicted of several federal crimes stemming from Mueller's investigation.
The special counsel is investigating potential links between the Trump campaign and the Kremlin. Trump has repeatedly denied that he colluded or obstructed justice.
Stone had predicted that he could face charges in the probe. He said he did nothing wrong, but contended to The Guardian that Mueller "may frame me for some bogus charge in order to silence me or induce me to testify against the president."
Legal scrutiny of Stone, who as a young operative helped to boost President Richard Nixon's re-election bid, appeared to focus on what he knew about the leak of Democratic emails during the 2016 campaign.
Clarification: This story was revised to clarify the circumstances about Assange's residency in the Ecuadorian Embassy in London.Â
—CNBC's Terri Cullen and Marty Steinberg contributed to this report.