Even as a college student, Sen. Bernie Sanders (I-Vt.) was standing up to injustice. And getting arrested for it.

Recently posted footage by documentary company Kartemquin Films shows Sanders as a 21-year-old University of Chicago student being grabbed by police and hauled off to a police wagon in 1963.

Sanders was arrested while staging a civil rights sit-in. After the footage was posted online, The Chicago Tribune discovered a photo in its archives showing the arrest.

Sanders' campaign confirmed to the Tribune and to The New York Times that the young man being arrested is in fact the presidential candidate.

"[Bernie] looked at it -- he actually has his student ID from the University of Chicago in his wallet -- and he said, 'Yes, that indeed is [me],'" Tad Devine, a senior advisor to the campaign, told the Tribune.

Sanders was leading a protest against segregation, the newspaper noted.

In the mid-1960s, protests over segregation in the area raged over mobile classrooms dubbed "Willis Wagons," named for then-Chicago Schools Superintendent Benjamin Willis. The phrase "Willis Wagons" was believed to have been coined in 1963 by Rosie Simpson, a leader in education reform in Chicago. She was describing the trailers that Willis set up for black children instead of sending them to white schools.

Sanders, who was a leader of the Congress of Racial Equality, was found guilty of resisting arrest. He was fined $25.

In another recent discovery of a presidential candidate's civil rights record, Donald Trump spent more than $85,000 in 1989 calling for the deaths of the Central Park Five, a group of black teenagers wrongly convicted of rape. Trump took out four full-page ads in papers including The New York Times that referred to the teens as "rapists," "thugs" and "wild criminals."

"They should be forced to suffer," Trump's ad said. "I want them to be afraid."

Editor's Note: Donald Trump is a serial liar, rampant xenophobe, racist, misogynist, birther and bully who has repeatedly pledged to ban all Muslims -- 1.6 billion members of an entire religion -- from entering the U.S.