Special counsel Robert Mueller’s investigation into Russian election interference had already revealed that Kremlin-linked trolls were ordered to write social media posts not only in opposition to Clinton but in support of Sanders and then-candidate Donald Trump. 

…”There is no question that Sanders was central to their strategy. He was clearly used as a mechanism to decrease voter turnout for Hillary Clinton.”

…Sanders was “just a tool” to the Russians, Linvill added, and “a wedge to drive into the Democratic Party.”

Bernie Sanders ‘central’ to Russia’s pro-Trump 2016 strategy: study – Business Insider

yup.