Last August, an old friend and confidante of Donald Trump who describes himself as a “dirty trickster” said: “Robert Mueller is coming for me.”

Today that prediction came true.

In a dawn raid, FBI agents carrying assault rifles swarmed the home of Roger Stone, one of the most flamboyant and controversial figures in US politics.

He has been charged by special counsel Robert Mueller’s investigation into Russian collusion on a number of counts, including lying to Congress and obstructing the investigation.

Even in a White House that generates bombshell headlines on a daily basis, this one is a big deal – Stone is a long-time associate of Trump and appears to have played a part in one of the most controversial aspects of the 2016 presidential campaign. 

Who is Roger Stone? 

Over the course of five decades, 66-year-old Stone has cultivated a successful career in politics without ever becoming a politician.

Instead, he amassed power and influence as a behind-the-scenes lobbyist and consultant, playing the Washington game without ever being constrained by the rules that normally apply to those seeking office.

What’s his style?

Stone plays dirty and doesn’t care who he offends. He began his career working for the 1972 Nixon campaign and one of his more memorable contributions was to hire someone to pose as the opponent’s driver and spy on him.

His idolising of Nixon culminated with him getting a tattoo of the later scandal-ridden president on his back.

Stone described his style of doing politics in a 2018 interview with The New Yorker, both of which will be familiar to anyone with even a passing interest in US politics since Donald Trump took office in 2016.

How does he know Trump?

The worlds of Trump and Stone first collided in the 90s, when the future president was still a property mogul with a string of casinos that would soon file for bankruptcy.

Stone became a lobbyist for Trump and in 1998 made the first of what would become a recurring suggestion – that he should run for president.

Trump finally got round to that two decades later, announcing his bid in 2015. Stone became an adviser, but left soon after.

He claimed he had quit, but when Trump announced his departure, he said: “I terminated Roger Stone last night because he no longer serves a useful function for my campaign.

“I really don’t want publicity seekers who want to be on magazines or who are out for themselves. This campaign is not about them. It’s about victory and making America great again.”

Despite the apparent acrimony, Stone remained a staunch supporter of the presidential candidate and crucially, appears to have carried on doing what he does best – causing trouble behind the scenes.

Why is he in trouble with the law?

The charges Stone faces mainly relate to an alleged relationship he had with Wikileaks around the time the whistle-blower group released stolen emails that seriously – some would argue fatally – damaged the campaign of Hillary Clinton.

The indictment against him lays out in detail Stone’s conversations about the stolen Democratic emails posted by WikiLeaks, which Mueller’s office has said were hacked by Russian intelligence officers.

It says the Trump campaign directed a senior campaign official to contact Stone after the WikiLeaks release of hacked emails from the Democratic National Committee and other groups on July 22, 2016.

That official, who is not named in court papers, asked Stone about additional releases and “what other damaging information” WikiLeaks had “regarding the Clinton campaign”, the indictment says.

It accuses him of witness tampering, obstruction and false statements about his interactions related to WikiLeaks’ release.

Some of the false statements were made to the House Intelligence Committee in at the US Congress.

Barbara McQuade, a former US Attorney, told Reuters: “The indictment was not unexpected, but it is still significant because it alleges coordination between the Trump Campaign and WikiLeaks.”

Stone has publicly condemned the Mueller investigation and echoed the president’s descriptions of it as a witch-hunt, but he has long attracted investigators’ attention, especially in light of a 2016 tweet that appeared to presage knowledge that emails stolen from Podesta would soon be released.

In that tweet, he said: ”Wednesday @HillaryClinton is done. #Wikileaks.”

Despite this, he has always said he had no inside information about the contents of the emails in WikiLeaks’ possession, or the timing of when they would be released.

Why is it such a big deal?

First things first, it’s a big deal because he’s just been arrested in the Special Counsel probe.

Robert Mueller’s investigation has been plugging away in secret for months now, and the only real sign of its progress is the periodic arrest and charging of a number of individuals.

Stone, as a long-time ally of Trump, is one of the closest to the president to be arrested.

But most of all, the indictment underscored the Trump campaign’s pursuit of damaging information, much like the June 2016 meeting at Trump Tower between campaign aides and a Russian lawyer with ties to the Kremlin.

Trump’s eldest son, Donald Trump Jr, has acknowledged he was expecting to get “dirt” on Clinton at the meeting.

Michael Zeldin, a former federal prosecutor, said the new details in the indictment were damaging politically to Trump, but that it remained unclear if there was criminal exposure for anyone else in the president’s orbit.

He noted that Mueller made a point of portraying WikiLeaks as an organisation that has repeatedly been involved in posting stolen documents from US citizens.

“In Mueller’s mind this is a campaign cavorting with the enemy,” Zeldin said.

“Politically there is a lot here that is pretty ugly. Legally it’s not clear to me if there is evidence of people having colluded in a criminal sense.”

What has Trump said?

Trump was silent for much of Friday after news of the arrest broke, but late in the afternoon, he tweeted: “Greatest Witch Hunt in the History of our Country! NO COLLUSION! Border Coyotes, Drug Dealers and Human Traffickers are treated better. Who alerted CNN to be there?”

A statement from White House press secretary Sarah Sanders said: “The charges brought against Mr Stone have nothing to do with the president, has nothing to do with the White House.

“The president did nothing wrong.”

It’s worth noting that this adheres to what seems to be the latest evolution in the denials about anything Russia-related.

While the White House used to deny collusion between the Trump campaign and Russia, it now settles for highlighting only the president’s innocence. 

What’s the bigger picture? 

Thirty-five people have pleaded guilty, been indicted or otherwise swept up in the Russia inquiry, which has clouded Trump’s two-year-old presidency.

There will almost certainly be more.