The plot against America began in 2014. Thousands of miles away, in a drab office building in St Petersburg, Russia, a fake newsroom was under construction with its own graphics, data analysis, search engine optimisation, IT and finance departments. Its mission: ”information warfare against the United States of America”.

What followed, according to an indictment brought by the US special counsel, Robert Mueller, on Friday, was a stunningly successful attack on the most powerful democracy in the world. It involved stolen identities, fake social media accounts, rallies organised from afar, US citizens duped into doing Moscow’s bidding, and two Russians going undercover in a ruse reminiscent of The Americans, a TV drama about KGB spies in suburban Washington during the cold war.

Mueller also delivered an indictment, figuratively if not literally, of tech giants Facebook and Twitter for handing Russia a weapon to turn against the American people – one that Barack Obama’s administration was impotent to deflect.

In his first criminal charges related to election meddling, Mueller accused 13 Russians and three Russian companies of an elaborate effort to disrupt the 2016 presidential poll with a covert trolling campaign, aimed in part at helping Donald Trump defeat Hillary Clinton. After more than a year of statements by the intelligence community, congressional hearings and media reports, this hardly came as a surprise; but the extent of Moscow’s audacity and reach did.

Far from being all about Trump, it was clear that allegations of collusion form just one component of an ongoing, multi-layered investigation. Mueller was appointed special counsel in May last year, following Trump’s dismissal of the FBI director James Comey. He has been assailed by Trump, some Republicans and conservative media seeking to delegitimise him. But still he quietly, meticulously and relentlessly zeroes in from his leak-proof office.

Donald Trump speaks during a campaign rally in South Carolina in 2016. Photograph: Jim Watson/AFP/Getty Images

“The indictment is an indication of the scale of Russia’s interference but also an indication of the scale of Mueller’s investigation,” said Mark Simakovsky at the Atlantic Council thinktank, a former Russia specialist at the Pentagon. “From the beginning, Mueller had a broad mandate. It shouldn’t come as any surprise that the investigation has targeted Russians who have been on the ground interfering in the election.”

If, in the tradition of TV detectives, Mueller has a corkboard on which he pins photos of suspects, then on one side of the board he now has the faces of 13 Russians. On the other he has four men already charged: the former Trump campaign manager Paul Manafort, his deputy Rick Gates, former national security adviser Michael Flynn and former foreign policy adviser George Papadopoulos. What is unknown is whether he will be able to draw a direct line between the two groups.

The unprecedented Russian offensive began in 2014 with an aim to “sow discord” and evolved, for still unknown reasons, into a concerted attempt to help Trump. Some of it relied on old-fashioned boots on the ground. Two operatives, Aleksandra Krylova and Anna Bogacheva, allegedly travelled as tourists through at least nine states over about two weeks in June 2014 to collect intelligence for their operations. They prepared “evacuation scenarios” in case their cover was blown.

This was combined with exploiting vulnerabilities in the anonymous, borderless world of social media, where agents of chaos thrive. Silicon Valley’s utopian fantasies were shattered by the Internet Research Agency, a “troll farm” based in nondescript offices at 55 Savushkina Street in St Petersburg. Allegedly operating through Russian shell companies, the agency employed hundreds of people, ranging from creators of fictitious personae to technical and administrative support, with an annual budget of millions of dollars, the indictment says.

Its specialists were divided into day shifts and night shifts to fit with the appropriate US time zones. The agency also circulated lists of US holidays so that specialists could be active accordingly. They were directed to create “political intensity through supporting radical groups, users dissatisfied with [the] social and economic situation and oppositional social movements”.

Hillary Clinton and Michelle Obama on the presidential campaign trail in 2016. Photograph: Alex Wong/Getty Images

Russians posed as politically and socially active Americans, advocating for and against particular candidates, according to Mueller. They created social media pages and groups, and bought political adverts such as “JOIN our #HillaryClintonForPrison2016” and “Donald wants to defeat terrorism ... Hillary wants to sponsor it”. They relied on identity theft, using the social security numbers, home addresses and birth dates of Americans without their knowledge. They set up fake bank accounts linked to PayPal accounts.

“They engaged in operations primarily intended to communicate derogatory information about Hillary Clinton, to denigrate other candidates such as Ted Cruz and Marco Rubio, and to support [Democratic candidate] Bernie Sanders and then-candidate Donald Trump,” the indictment states. According to one internal communication, the specialists were told to “use any opportunity to criticise Hillary and the rest (except Sanders and Trump – we support them)”.

In June 2016, just weeks after Trump officially clinched the Republican nomination, the Russians began to organise and coordinate pro-Trump rallies, recruiting and paying unwitting Americans. At a time when Trump supporters were chanting “Lock her up!”, one was asked to wear a costume portraying Clinton in a prison uniform at a rally in Florida, while another was asked to build a cage on a flatbed truck.

On 5 June, someone posing as an American activist used the Twitter account @March_for_Trump to contact an unnamed Trump campaign volunteer in New York. The volunteer “agreed to provide signs for the ‘March for Trump’ rally”, the indictment alleges. That contact came four days before Trump’s son, Donald Jr, and son-in-law, Jared Kushner, met a group of representatives for Russian interests at Trump Tower. That meeting is not cited in the indictment; it remains to be seen if Mueller will make a connection.

The accounts @March_for_Trump and @TEN_GOP – which falsely appeared to represent the Republican party in Tennessee – generated thousands of tweets. A selection made available by NBC News includes: “This is sickening. Hillary using the Mentally Ill to incite violence at Trump rallies. #FreeJulian #BirdDogging…”, “BREAKING Hillary caught using a child actor at her townhall in Haverford, PA Please, RT to expose this fraud!…”, “DISGUSTING Watch: Hillary laughing when Trump said gays get thrown off buildings in Muslim counties [sic] …” and “Watch: Barack Obama admits he was born in Kenya.. #birtherism”.

On or about 22 September, Russians created and bought Facebook ads for a series of “Miners for Trump” rallies in Pennsylvania – which turned out to be a crucial swing state that Trump won by 68,236 votes. The operation also targeted minority communities to exploit divisive issues such as immigration, religion and the Black Lives Matter movement, with a view to suppressing Democratic votes.

Twelve of the individuals indicted worked at various times for the Internet Research Agency. The other defendant, Yevgeny Viktorovich Prigozhin, allegedly funded the conspiracy. Prigozhin is a St Petersburg businessman dubbed “Putin’s chef” because his restaurants have hosted the Kremlin leader and foreign dignitaries. The 13 Russians are not in custody and not likely ever to face trial.

The indictment does not allege that any American knowingly participated in Russian meddling, or that Trump campaign associates had more than “unwitting” contact with some who posed as Americans. Trump quickly claimed vindication, noting in a tweet that the interference efforts began in 2014 “long before I announced that I would run for president”. He added: “The results of the election were not impacted. The Trump campaign did nothing wrong – no collusion!”

But it’s far from over. Although the Russian interference predated Trump’s candidacy, there is still the possibility that his campaign decided to ride that wave and capitalise on a coincidence of interests. The president has shown a mysterious reluctance to criticise the Russian president, Vladimir Putin, or acknowledge that Moscow might have played any part in putting him in the White House. Even on Friday, he said little to acknowledge the scale of the assault or offer anything by way of American countermeasures.

Matthew Miller, a former justice department spokesman under Obama, said: “He’s acting more like a defendant than the chief executive of a country that was attacked. It continues to be all about him.”

Few would bet against more tremors to come. The indictment does not mention the hacking of Democratic emails, which then turned up on WikiLeaks. It does not mention the infamous Trump Tower meeting in June 2016. It does not mention the four Trump associates who are facing charges that range from money laundering to lying to the FBI about conversations with Russia’s ambassador. America, and the world, is waiting for Mueller to join the dots.

Simakovsky pondered: “Why did this get released before the president decides whether to take an interview with special counsel? All this is timed to build more public and private pressure on those who are being investigated. I believe there should be no comfort in the Trump administration that this somehow absolves them from inquiry.”