Republican presidential nominee Donald Trump at a recent campaign event. (Luke Sharrett/Bloomberg)

You may have seen Republican presidential nominee Donald Trump talking about “the good old days” in video that went viral this week. The unsettling clip juxtaposes footage of violent clashes at Trump’s campaign events with images of black men and women being attacked during the civil rights movement.

An unattributed version of the clip has made the rounds on social media, but it’s actually from Ava DuVernay’s Netflix documentary “13th,” which connects the prison labor industry to a legacy of racial discrimination and efforts to criminalize African Americans.  The clip below is from the film’s official Twitter account.

“In the good old days this doesn’t happen because they used to treat them very, very rough. And when they protested once, you know, they would not do it again so easily,” Trump says in “13th” as a scene of a black woman being pushed at a Trump campaign event transitions into civil rights footage of a black man being punched and pushed across the street by a racist mob. “I’d like to punch him in the face I’ll tell you,” Trump says in an audio clip from another event.

As reported by Vox in March, MSNBC host Rachel Maddow used these and other comments by Trump in a video montage intended to show that the then-Republican frontrunner regularly encouraged violence against protesters at his campaign events. MSNBC aired the segment after violent clashes broke out between protesters and Trump supporters at a Chicago rally, which Trump eventually canceled due to “growing safety concerns.”

In “13th,” hearing Trump’s campaign rhetoric set against modern and historical footage of violence against African Americans is especially powerful. But it’s just one part of the film, which also puts Trump’s recent comments on the Central Park Five into startling context and goes after Democratic presidential nominee Hillary Clinton for her support of Bill Clinton’s controversial 1994 crime bill.

On Thursday, DuVernay tweeted that the Trump clip “was not made as political propaganda,” in response to a Democratic National Committee staffer and former aide to Hillary Clinton who shared an unattributed version of the video. (He later tweeted the clip with attribution and retweeted others who noted that the clip was from “13th.”)

The documentary also features footage of Hillary Clinton’s infamous comments about “super-predators.” In the 1996 clip, Clinton was speaking in support of her husband’s crime bill, which the former president has acknowledged helped lead to the mass incarceration that DuVernay explores in her film.

Related:

Review: Ava DuVernay’s ‘13th’ explores the intersection of racism and criminal justice

Ava DuVernay’s Netflix film 13th’ reveals how mass incarceration is an extension of slavery

Both Trump and Clinton have baggage on race. Ava DuVernay’s Netflix film ’13th’ exposes it.