If there was someone in Trump’s inner circle due to fall, it was his close confidant and campaign advisor, Roger Stone.

In what is the latest development surrounding Special Counsel Robert Mueller's investigation into suspected collusion between the Trump campaign and Russia, the FBI's arrest of Roger Stone on Friday at his home in Florida offers a new piece to the puzzle detailing what really happened during the 2016 presidential campaign.

According to the Washington Post, the "most politically explosive allegation" against Stone is that he “lied to Congress when he denied discussing his advance knowledge of WikiLeaks’ email dumps with anyone involved in Donald Trump’s 2016 campaign.”

Toward the end of the 2016 campaign, Russian hackers obtained access to Democratic candidate Hillary Clinton's e-mail server, and proceeded to send the hacked information to WikiLeaks in order that they make it public.

This is widely considered to have been the coup de grace for the Clinton campaign, helping Donald Trump pull off the shocking result to become president.

The direct participation by Russian intelligence demonstrated Moscow's interference in the manipulation of the results, and it served as the trigger prompting the FBI to launch an investigation looking into alleged collusion between the Trump campaign and Russia.

According to the indictment, Stone "spoke to several people involved in the Trump Campaign about what he said he learned from his intermediary with Wikileaks."

"After the July 22, 2016 release of stolen DNC, a senior Trump Campaign official was directed to contact Stone about any additional releases and what other damaging information that [Wikileaks] had regarding the Clinton Campaign," reads the document.

Stone reportedly communicated his information to "a high-ranking Trump Campaign official," which is presumed to be former Campaign CEO and White House Chief Strategist Steve Bannon, with whom he established a secure contact to "be consulted about the group's activities."

The indictment made public alleged communications between Stone and the Trump Campaign, in which Stone talks about his "friend in London" - likely, WikiLeaks founder Julian Assange - and others in which he puts pressure on a "Person 2" so that "he doesn’t tell the truth to the House Intelligence Committee."

Although Stone "formally" withdrew from the Trump Campaign in 2015, he continued to serve as an "independent advisor" during the subsequent months, according to the indictment, and his communication with members close to the president remained even after Mueller handed down the investigation's first sentences.

Stone has made a career out of "the dark arts" of politics, having participated as one of the youngest members of "Richard Nixon’s infamous 1972 reelection bid, which launched the Watergate scandal,” Politico explained.

Similarly, Stone was one of the central figures who helped design Trump's image as a presidential candidate, having urged him to "make the jump from business to politics," first in 1988, and later in 2000 and 2012, until Trump finally jumped into the 2016 campaign.

Stone appeared before Magistrate Judge Lurana S. Snow in federal court in Fort Lauderdale, Florida this morning. He faces seven charges: one for obstruction of an official procedure, five for false statements, and one for witness tampering.

According to Bloomberg, "it’s possible Mueller could bring new and more serious charges against Stone unless he cooperates."