Sen. Bernie Sanders (I-VT) has been under fire from all sides over the “Bernie Bros” — groups of his supporters, usually online but increasingly off-line, who engage in vicious, often abusive and harassing behavior against those they perceive as threats to Sanders’ presidential campaign.

During Wednesday night’s debate, though, when asked about the behavior of so-called “Bernie Bros,” Sanders again failed to distance himself from the movement, instead suggesting that he was being targeted by nefarious, pro-Trump Russian hackers posing as Bernie Sanders supporters.

Former South Bend mayor Pete Buttigieg confronted Sanders about his “Bernie Bro” followers during the debate demanding — as former Vice President Joe Biden, Sen. Elizabeth Warren (D-MA), and former New York City mayor Michael Bloomberg have — that Sanders disavow the “Bernie Bros” and openly condemn their behavior.

Sanders refused.

“At a certain point you have to ask yourself why did this pattern arise, why is especially the case with your supporters?” Buttigieg asked, suggesting that Sanders himself had encouraged vitriol and “revolution” as part of his messaging, leaving his supporters feeling as if threats and harassment are legitimate methods of voter outreach.

Sanders “pushed back aggressively,” according to The Daily Beast, and “suggested that, perhaps, the accounts that claimed to be supporters of his that were creating such havoc online may not actually be real at all but, instead, Russian bots designed to sow confusion and discord.”

“All of us remember 2016, and what we remember is efforts by Russians and others to interfere in our election and divide us up,” Sanders said, alluding to the theory that Russian hackers helped throw the 2016 presidential election to Donald Trump. “I’m not saying that’s happening, but it would not shock me.”

It’s not happening, according to the Daily Beast.

“There are not any Russian bots operating on here at the moment,” “a disinformation researcher” told the outlet. “It’s basically impossible at this point for them to operate on here. Twitter’s site integrity team has made it real boring for me. I have checked and checked and checked hashtags related to the primaries, and it’s just been really boring so far.”

Instagram is no different. Experts found only four Russian-affiliated accounts expressing support for Sanders, but those accounts “focused primarily on posting memes about American criminal justice issues” and all four were suspended in October.

There’s also the small matter of “Bernie Bros” moving from the online space into real life. Last week, the Nevada Culinary Union faced a barrage of harassment and abuse from Sanders supporters angry that the union refused to make an endorsement ahead of the Nevada Democratic caucuses, some of it online, but much of it over email and phone. Last weekend, at the Nevada Democratic Party’s state convention, irate Sanders supporters started a near riot at the Las Vegas casino where the meeting was being held after around 60 of Sanders’ delegates to the convention were disqualified. Many had to be removed by security.

Bernie Sanders has, so far, resisted apologizing for the “Bernie Bros,” instead issuing general admonishments to those who commit violence in the name of a political movement.