The most-viewed Facebook message secretly created by a St. Petersburg-based Russian troll farm was one that allegedly backed American cops.

“Back The Badge” appeared to be an authentically American community on Facebook rallying support for police officers. In fact it was Russian, a creation of the Internet Research Agency, an online propaganda mill that special counsel Robert Mueller indicted in February on conspiracy charges.

The ad itself was nondescript, a simple portal to Back The Badge’s Facebook page. It showed the group’s logo, an officer’s shield, over a background image of a cop car’s flashing blue and red lights. “Community of people who support our brave police officers,” the ad read.

That ad, released on Thursday by Democrats on the House intelligence committee, ran on Oct. 19, 2016, less than a month before the election. According to material turned over to the committee by Facebook, it appears to be the most influential single ad the troll farm is ever know to have concocted.

There is no way to decisively determine the impact of any particular advertisement or other piece of propaganda. But more people saw the Back The Badge ad than any other inauthentic account, page, or advertisement that the Internet Research Agency concocted. Facebook’s data tools, in the hands of the Internet Research Agency, ensured that it appeared in the Facebook feeds of over 1.3 million users, a fact first noted by NBC. Over 73,000 people clicked on it.

To get the ad seen so widely, the Internet Research Agency capitalized on the deep well of Blue Lives Matter supporters active on Facebook—real Americans, mostly on the right, infuriated by Black Lives Matters’ demands for the dismantlement of white supremacy and its focus on the aggressive, often lethal and rarely punished over-policing of black America.

Users whose interests or account history included “state police,” “law enforcement in the United States,” “police,” “Sheriffs in the United States,” and “Law enforcement” or “police officer” and also “Support Law Enforcement,” “The Thin Blue Line,” “Officer Down Memorial Page,” “Police Wives Unite,” “National Police Lives Association” or “Heroes Behind The Badge” found the Back The Badge Facebook ad.

The intelligence committee has not previously identified or released any Blue Lives Matter-centric ads or pages created by the Internet Research Agency. Its new disclosure corroborates a Wall Street Journal report from last October that found the troll farm helped organize a Blue Lives Matter rally in Dallas on July 10, 2016, that it promoted on Facebook. The Daily Beast first reported in September 2017 that Russian propagandists were using Facebook to organize real-life political demonstrations.

During the same month that the pro-police ad appeared on Facebook, the Internet Research Agency also promoted ads with the diametrically opposed message: to support the Black Lives Matter movement. The only thing the two competing messages had in common was that they appeared organically American, all while obscuring their Russian origins.

Those farm-crafted Facebook accounts had names like Blacktivists, Black Matters US, and Williams & Kalvin. While none of those accounts’ ads were as widely viewed as the Back The Badge ad, an advertisement from the Williams & Kalvin imposter account—which was first reported by The Daily Beast—posted in April 2016 was the 10th-most viewed Facebook creation of the Internet Research Agency. It garnered 371,000 impressions and 16,000 clicks.

The dual promotion of the contradictory messaging underscores the rationale that Mueller’s indictment attributed to the Internet Research Agency. “Defendant organization had a strategic goal to sow discord in the U.S. political system,” Mueller’s indictment reads.

But the specific promotion of Blue Lives Matter also speaks to another strategic goal of the Internet Research Agency: “supporting the presidential campaign of then-candidate Donald J. Trump,” according to Mueller’s indictment.

While nowhere near as mobilized as Black Lives Matter and rarely found on the streets in protest in comparable numbers, Blue Lives Matter connects with Trump’s core voters: white people whose sense of control over American politics and society feels to them threatened, and particularly by nonwhite demonstrations of political power. Police unions strongly backed Trump, with the Fraternal Order of Police endorsing him in September 2016. As president, he and Attorney General Jeff Sessions have overseen a rollback of Obama-era police reforms, and held rallies where Trump has claimed police are “totally underappreciated, except by me.”

It all speaks to Trump’s long political history of exploiting the politics of white grievance, a strategy also practiced by Trump ally-turned-lawyer Rudy Giuliani, who used it to become New York City’s mayor. Even before Giuliani’s mayoralty, one of Trump’s earliest forays into politics was a newspaper-advertisement call to execute the five black teenagers falsely accused and ultimately exonerated of raping a white woman, known as the Central Park Five. “Bring Back The Death Penalty, Bring Back Our Police,” blared the headline of Trump’s 1989 ad.

Much attention has been paid to the Internet Research Agency’s co-optation of American movements against white supremacy. But the new material released by the House intelligence committee Democrats indicates a comparatively larger—and authentically American—appetite on Facebook for Blue Lives Matter-style material.

By contrast, an IRA-crafted ad for imposter account Woke Blacks, promoting a similar landing page for an inauthentic Facebook page for the group, was seen by only 752,179 users, 33,000 of whom clicked through. That December 2016 ad does not explicitly promote Black Lives Matter or activism, and it followed the election. But it is the most widely viewed ad created by the troll farm targeting African Americans, according to Facebook data released by the committee.

The next-most popular fake African-American Facebook ad they created, a December 2015 ad from Blacktivists—which simply read “Say it loud, I’m black and I’m proud”—was seen by 530,000 users, or fewer than half of those who saw Back The Badge.