After violence erupted in 2016 between neo-Nazi groups and anti-racist activists in Sacramento, the head of the white supremacist Traditionalist Worker Party went on a well-known racist radio program to gloat about the number of attacks his group had carried out.

“They got one of ours, but we got six of them,” Matthew Heimbach proudly announced, according to the SPLC. “Six antifa on the way to the hospital.”

A year and a half after what is now grimly called the 2016 Sacramento riots, lawyers for anti-fascist activists involved in the protest say they’ve turned up documents proving investigating officers are working on behalf of the racist attackers. A report from the Guardian finds that court papers document “officers expressing sympathy with white supremacists and trying to protect a neo-Nazi organizer’s identity” while also seeking “the prosecution of activists with ‘anti-racist’ beliefs.” Three anti-fascist counter-protesters, Yvette Felarca, Mike Williams and Porfirio Paz, are looking to have felony charges dismissed, citing a “cover-up and collusion with the fascists” by prosecutors and law enforcement.

California Highway Patrol records show TWP member Derik Punneo was asked by officers to review audio and pictures of antifa activists in order to help identify them by name. Law enforcement investigators reassured Punneo that they are “pretty much going after [the anti-racist activists],” but that they would be treating him “as a victim.” As Heimbach alluded in his radio appearance, multiple people were stabbed during the Sacramento incident, and police records indicate Punneo was carrying a knife at the rally. The friendly police interview took place when Punneo was brought in for unrelated domestic violence charges.

While they attempted to identify antifa protesters, CHP officers helped Traditionalist Worker Party members avoid public identification. CHP officer Donovan Ayres told another TWP member, Doug McCormack, that he didn’t know the source of a public records request about the incident, but noted that, “If I did, I would tell you.” He also told McCormack he planned to “suggest that we…redact your name or something until this gets resolved.” McCormack, police files indicate, was also carrying a knife during the Sacramento melee.

In addition to McCormack and Punneo, police records show “three other TWP-affiliated men…were armed with knives.” None face charges.

In contrast with his handling of the neo-Nazis’ cases, Officer Ayers treated the anti-racist activists like seasoned criminals. The investigator’s report describes at length past activism by Felarca, whom the Los Angeles Times reports “sustained a bloody blow to the head” during the riot. Ayers went so far as to dig up Facebook photos of an African-American counter-protester giving a fist salute to justify claims that he had “intent and motivation to violate the civil rights” of the racists on hand that day. That protester left the rally in an ambulance, having suffered stab wounds to the hand, chest and stomach. (“The Nazis [went] after the black people,” a medical assistant on the scene told the Sacramento Bee.) Ayers “recommended the man be charged with 11 offenses, including disturbing the peace, conspiracy, assault, unlawful assembly and wearing a mask to evade police.” He has not been charged.

The Guardian’s revelations are a reminder of longstanding reports linking law enforcement with the Ku Klux Klan and other racist groups. In 2006, the FBI issued an intelligence paper titled “White Supremacist Infiltration of Law Enforcement,” which acknowledged that “white supremacist groups have historically engaged in strategic efforts to infiltrate and recruit from law enforcement communities.” Speaking to the Intercept writer Alice Speri last year, Chapman University sociologist Pete Simi helped historicize the ties that bind police and hate groups, pointing to U.S. policing’s roots in slave patrols, night watches and violent suppression of African-American communities.

“If you look at the history of law enforcement in the United States, it is a history of white supremacy, to put it bluntly,” Simi told Speri. “More recently, just going back 50 years, law enforcement, particularly in the South, was filled with Klan members.”

It’s impossible to cite hard and fast numbers on law enforcement membership overlapping with white supremacist groups, but that’s kind of the point of getting a foothold in both. The 2006 FBI report includes a reference to “ghost skins,” a term originally employed in white supremacist circles to denote movement affiliates who publicly downplay their racism in order to more stealthily spread their beliefs. Racists might trade in sheets for police uniforms, or alternately, khakis and boat shoes. Only a fraction of those covert operatives in police ranks are discovered, and even then, it’s likely the notorious blue wall prevents an unknowable percentage from ever being publicly revealed. Speri enumerates a handful of cases dating back to the 1990s in which white supremacist cops tipped their hands:

In Los Angeles, for example, a U.S. District Court judge found in 1991 that members of a local sheriff’s department had formed a neo-Nazi gang and habitually terrorized black and Latino residents. In Chicago, Jon Burge, a police detective and rumored KKK member, was fired, and eventually prosecuted in 2008, over charges relating to the torture of at least 120 black men during his decades long career. Burge notoriously referred to an electric shock device he used during interrogations as the “nigger box.” In Cleveland, officials found that a number of police officers had scrawled “racist or Nazi graffiti” throughout their department’s locker rooms. In Texas, two police officers were fired when it was discovered they were Klansmen. One of them said he had tried to boost the organization’s membership by giving an application to a fellow officer he thought shared his “white, Christian, heterosexual values."

More recently, as the Guardian notes, police invited an alt-right protester to aid them in arresting an anti-racist counter-protester at the same rally. There was also the well-publicized case of DeAndre Harris, an African-American man badly beaten by a mob of racist thugs in Charlottesville, who somehow ended up being charged with a felony. The charges, after sustained outcry, were dropped in December.

Donald Trump stepped on the national political stage just as the covert racism and implicit bias that often underlie police brutality were getting a national airing. The administration has helped reset progress, which had moved a few nanometers at best, on the issue. Since taking office, Trump has canceled funds earmarked to oppose violent white racist groups, despite studies proving white nationalists are a bigger threat to public safety than ISIL. Alt-right influenced attackers have killed and injured more than 100 people since 2014, according to the SPLC. Jeff Sessions’ Department of Justice has essentially restarted Cointelpro, creating out of thin air the designation “black identity extremists,” a vague category that seems to implicate any politically outspoken African American. Alongside all this, the president peddles the well-worn lie that fighting against neo-Nazis is as bad as being a Nazi, which is dumb but absolutely in keeping with his character.

The last two years have seen an easing of the longstanding social prohibitions around public displays of racism, and Trump plays no small part in that. (In fact, TWP claimed the Sacramento rally was “a statement about the precarious situation [the white] race is in” as evidenced by make-believe “brutal assaults” by protesters at Donald Trump rallies. Ironically, TWP head Heimbach participated in the actual 2016 physical assault of a young black woman protester at a Trump rally.) That has only worsened law enforcement’s already outsized racism problem. Prosecutors in the Sacramento case claim information in the motion to dismiss is “inaccurate or fabricated.” As the case’s outcome is weighed, we can expect these issues to become yet more familiar.