Mueller's report expected to shed more light on Russian efforts to boost Bernie Sanders
Sen. Bernie Sanders talks with Rachel Maddow on MSNBC (Screen cap).

Russian efforts to promote Sen. Bernie Sanders during the 2016 campaign could get more attention once special counsel Robert Mueller's findings are released.

The special counsel already confirmed those efforts in an indictment filed against 13 Russians associated with the Internet Research Agency, and Sanders himself has discussed how campaign workers noticed what was happening in real time, reported the Washington Post.

Sanders told Vermont Public Radio last year that one of his campaign workers got suspicious that some of the social media activity promoting his campaign appeared to be originating outside the U.S. and alerted Hillary Clinton's campaign.

The senator said he never knew about those apparently Russian efforts, and later backed off claims that his staff did, and 2016 campaign manager Jeff Weaver claims Sanders "misspoke a little bit" and mixed up some of the facts, although he denied that anyone in the campaign knew about the suspicious activity.

However, some Sanders backers not officially affiliated with the campaign did notice suspicious activity on social media during the Democratic primary, and tried to ban accounts that appeared to come from outside the U.S. from posting "absurd" memes attacking Clinton.

Recently released Twitter data has allowed researchers to examine English-language tweets identified as Russian in origin, many of which were intended to influence the presidential election nearly three years ago.

About 9,000 of the Russian tweets referred to “Bernie,” which were “liked” 59,281 times and retweeted 61,804 times, according to a pair of Clemson University researchers.

Thousands of other tweets, according to those researchers, targeted Sanders supporters without referring to the candidate but instead urged them to do anything but vote for Clinton in the November 2016 election.

“I think there is no question that Sanders was central to their strategy," said Darren Linvill, associate professor of communications at Clemson. "He was clearly used as a mechanism to decrease voter turnout for Hillary Clinton."

Linvill said his analysis showed those Russian efforts to promote Sanders and undermine Clinton were much greater than he expected to find.

Many Sanders supporters believed then, and still do, that the senator was treated unfairly by the Democratic Party and Clinton, and Russian accounts exploited that point to peel left-leaning voters away from the party's nominee.

Sanders later denounced the Kremlin's efforts and campaigned for his former rival, but some Democrats wish he'd done more to heal that divide before the election.

Mueller's indictment shows Russian accounts began promoting Sanders shortly after he announced his campaign in spring 2015 in hopes of weakening Clinton, who had infuriated Vladimir Putin during her time as secretary of state.

Putin also liked that Sanders, like Republican Donald Trump, opposed the Trans-Pacific Partnership, and he also gave at least three interviews during the primary to the state-run RT network.

The Internet Research Agency instructed employees to criticize Clinton and all other candidates except Trump and Sanders, according to Mueller's indictment.

The Russian tweets were mostly innocuous -- "I'm for Bernie all the way!" reads one -- until the July 2016 release by WikiLeaks of emails stolen from the Democratic National Committee that suggested the party had undermined Sanders.

Trump tried to divide Democrats using that narrative, and Russian trolls stepped up their efforts to turn Sanders supporters against Clinton.

It's impossible to quantify how much those Russian efforts influenced individual votes, but researchers at Ohio State found evidence that "fake news" spread on social media depressed voter turnout for Clinton.

The Ohio State researchers found that a quarter of respondents to their survey believed the false story that Clinton was in “very poor health,” 10 percent believed Trump had been endorsed by the pope, and 35 percent -- including 20 percent of Obama supporters -- believed that Clinton had approved weapons sales to Islamic militants.

Their soon-to-be-released report shows belief in those phony stories strongly correlates to voters who backed Obama in 2012 but did not support the Democratic nominee four years later.

"Only 77 percent of those surveyed who had voted for Barack Obama in 2012 supported Clinton in 2016," the researchers found, "10 percent backed Trump, 4 percent voted for third-party candidates, and 8 percent did not vote."