Independent Vermont Sen. Bernie Sanders supported socialist presidential candidates and was investigated by the FBI for his Marxist ties while he was mayor of Burlington, Vermont during the 1980s, according to a new report published Thursday.

The 77-year-old Democratic presidential contender maintained close ties to the Leon Trotsky-inspired communist Socialist Workers Party (SWP) at the same time the U.S. was engaged in a Cold War with the communist Soviet Union, files obtained by Joseph Simonson of the Washington Examiner show. (RELATED: Who’s To Blame For Cuba’s Latest Rationing Scheme?)

Sanders supported anti-American fanatic Andrew Pulley during the 1980 presidential election, and former Black Panther Mel Mason during the 1984 election. Sanders was also a featured speaker at the 1982 SWP convention, although there remains no evidence that Sanders was ever a member of the party, according to the report.

Additionally, the report states that Sanders’ activities drew the attention of the FBI, who probed his ties to far-left groups, something that drew the mayor’s ire. (RELATED: Bernie Sanders Says He Wants Netanyahu To Lose Election)

The report states:

Sanders’ involvement with the SWP led to his being investigated by the FBI, prompting outrage from the then-Burlington mayor. “I would agree with the judge,” Sanders said at the time, referring to a civil case arising from the incident, “who is quite correct in pointing out that when FBI agents come into a secretary of state’s office attempting to ‘investigate’ the political background of a mayor of the largest city in the state, there’s no question but that this opens up the potential for exploitation by the media and could be a source of embarrassment.”

Sanders has been a self-described “Democratic Socialist” for most of his public life, but has a history of expressing support for far-left radicals, including Cuban dictator Fidel Castro and the Sandinistas in Nicaragua.

Sanders is widely considered a front-runner for the Democratic presidential nomination and has been at or near the top of several polls since announcing his candidacy earlier this year.

You can read the full report here.

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