"You didn't pass the test," the woman who administered the exam told him later that day, he said, although it wasn't clear if his shortcoming was imperfect English or failing to bash Clinton.
Either way, Mindiyarov remained stuck with the less-glamorous job of commenting on articles posted to Russian websites and quit three months later from a job he compared to something from 1984, the dystopian novel by George Orwell.
"Your first feeling, when you ended up there, was that you were in some kind of factory that turned lying, telling untruths, into an industrial assembly line," Mindiyarov said.
The accounts of Mindiyarov and other former Russian trolls - along with a National Security Agency assessment and details from the 37-page indictment against the Internet Research Agency, two other companies and 13 individual Russian associates - underscore the sophistication and ambition of a programme that only now is coming into focus four years after its creation.
The secretive, multimillion-dollar disinformation campaign, which US officials said was called the "Translator Project," sought to undermine Clinton, bolster Donald Trump and turn Americans against each other - all from the remove of thousands of kilometres away, in an office building in St Petersburg.
Allegedly leading this effort was Russian oligarch Yevgeny Prigozhin, often called "Putin's chef" because of his close ties to President Vladimir Putin. US intelligence officials concluded in December that Putin's top aides had to approve, if not directly oversee, Prigozhin's operation, according to a classified NSA report, parts of which were shared with the Washington Post.
The NSA report also said that the Internet Research Agency, which ran online disinformation campaigns in Russia itself and in foreign nations such as Ukraine and the United States, used polls from American organisations to identify issues important to voters here.
The tentacles of the "Translator Project" reached deeply into American political life as at least 80 employees of the Internet Research Agency worked with unwitting Trump supporters to organise rallies, stoke concerns about Clinton's honesty and health and suppress the turnout of key voting blocs, including African-Americans, according to the indictment by Special Counsel Robert Mueller.
The campaign unfolded in a way that largely evaded public notice at the time, as Russians used American social media platforms, American payment systems and stolen American identities, birth dates and Social Security numbers to infiltrate American debate at its most unpredictable and intense.
The Russians involved in the campaign executed it with almost perfect pitch - learning to mimic the way Americans talk online about politics so well that real Americans with whom they interacted found them in no way suspicious.
Such deception did not happen by accident. Russian trolls worked hard to sound like Americans and camouflage their political messages in other content.
"The first order of business was not to be unmasked," said Lyudmila Savchuk, 36, a former employee of the Internet Research Agency who, like Mindiyarov, was not among those named in the indictment. "Their top specialty was to slip political ideas inside a wrapping that was as human as possible."
Prosecutors alleged that the operation was launched in May 2014 - before US political figures had formally declared their candidacies - giving Russians time to master how ordinary Americans think and talk and what they like and dislike. The trolls compiled reports on Internet metrics similar to those used by many American companies to figure out which Russian-created memes and posts were viewed and shared most, and by whom.
Those working on the disinformation campaign paid particular attention to what issues would outrage Americans, making them more likely to go to the polls, and which were likely to cause them to grow disillusioned and stay home. Russian trolls were even provided with a list of American holidays, prosecutors said, so they could craft appropriate content to follow the rhythms of an American year.
All of this ran through an operation that closely resembled a modern American campaign, with budgets, data analysts and design teams. Trolls received guidance on the ratio of text to graphics in posts, how to effectively use video and how to manage multiple accounts for maximum impact.
The NSA report in December said that the Internet Research Agency "clearly sought to identify topics resting on the fault lines of American politics - such as the Second Amendment, same-sex marriage, and the economy - as well as issues often characterized as sensitive or contentious - such as racism and religion - almost certainly to drive a wedge between segments of the US population."
The Internet Research Agency's analytics workers separated social media content into four categories: "govnostrana," which the NSA translated as "crap country"; "personality," or negative information about individuals; "precision strike," exploiting specific events; and "spam."
Former employees said little was left to chance.
Mindiyarov, the teacher, said he was paid about US$700 a month to work a 12-hour shift, from 9 am to 9 pm - two days on, two days off. His job was to write comments to append to Russian-language news items, toiling in a room with 20 computers and the window blinds closed, and required to hit post quotas.
Sometimes, he said, he and his colleagues would engage in a group troll in which they would pretend to hold different views of the same subject and argue about it in public online comments. Eventually, one of the group would declare he had been convinced by the others. "Those are the kinds of plays we had to act out," he said.
Prosecutors said three Russians, including two charged in the indictment, spent more than three weeks in the United States in 2014 and visited 10 states to gather intelligence for the disinformation campaign, which appeared to evolve over time.
After a grassroots activist in Texas advised them to concentrate their efforts on "purple states," such as Colorado, Virginia and Florida, prosecutors say the Russians began discussing among themselves the need to target such swing areas.
Russians first used ads purchased on social media and media contacts to announce rallies in New York City in June and July 2016 - a place where their efforts might get attention but was hardly an electoral battleground.
But by late August, they were concentrating on the crucial swing state of Florida. That month, the Russians allegedly used the impostor Facebook group "Being Patriotic" to get Americans to organise a wave of pro-Trump rallies in the state. The events drew light crowds but thousands of others learned of the effort online, giving the illusion of a groundswell of volunteer support for Trump all over Florida.
Several Americans who agreed to participate in events organised by the Internet Research Agency said the Russians posed convincingly as Americans - especially because they did not ask the Americans to do or say anything they were not already doing, a sign of how effectively the Russian effort learned to echo Trump's own campaign themes.
"I was supporting Donald Trump anyway. I didn't need persuading," said Max Christiansen, 28, a lawyer in Jupiter, Florida, who volunteered to host a get-together after seeing a request for volunteers posted online by "Being Patriotic."
When Sherrie Hyer, 63, a retired sales representative from the Villages community in Sumter County, Florida, got a message through Facebook from a stranger in August 2016 asking her if she would organise a pro-Trump rally later that month on a particular street corner in Oxford, Florida, she was neither surprised nor concerned.
Hyer had been politically active both online and in real life for years.
She had been involved with tea party groups and had previously organised a pro-Trump march through her retirement community that included a caravan of dozens of golf carts.
On the day of the rally, she called a number she had been provided as a contact for the organising group. The group had not put forward any people to join her group, and she was wondering if the man would be coming to his own rally. In unaccented English, he apologised and said he could not attend, she recalled.
In the end, Hyer convinced 35 or 40 of her own friends to come out and wave signs. The Russian-affiliated group had not needed to provide any people or suggest any messages. All of that came from Hyer and her friends - even the orange prison jumpsuit with the word "Clinton" scrawled on the back and the blond Hillary Clinton wig that Hyer said she wore to the rally.
Though prosecutors allege that the Russians bought similar costumes and paid unwitting Americans to wear them at other such events, Hyer said she bought her own Clinton prison uniform from Goodwill, had worn it to previous Trump events and dressed in it for this event without any outside suggestion.
"There was no Russians at my rally. I knew everyone there," she said. "I would have done it for Trump anyway. There was still a lot of excitement and Russians had no part of that. This wasn't a trick for me."
