California law enforcement pursued criminal charges against eight anti-fascist activists who were stabbed or beaten at a neo-Nazi rally while failing to prosecute anyone for the knife attacks against them, according to police records reviewed by the Guardian.

In addition to the decision not to charge white supremacists or others for stabbings at a far-right rally that left people with critical wounds, police also investigated 100 anti-fascist counter-protesters, recommending more than 500 total criminal charges against them, according to court filings from civil rights attorneys.

Meanwhile, for men investigated on the neo-Nazi side of a June 2016 brawl at the state capitol, police recommended only five mostly minor charges, none related to stabbings.

Lawyers produced new records this week as prosecutors in Sacramento prepared for a hearing in their long-running case against three anti-fascist counter-protesters, who have been charged with rioting and assault.

For two of the counter-protesters facing potential prison time, law enforcement officers surveilled their social media activity and cited their leftwing politics and affiliation with Chicano and indigenous rights groups as evidence against them, the police reports revealed.

None of the defendants heading toward trial were accused of the stabbings of anti-fascists.

The documents have raised fresh questions about California police agencies’ handling of rightwing violence and extremism, renewing accusations that law enforcement officials have shielded neo-Nazis from prosecution while aggressively pursuing demonstrators with leftwing and anti-racist political views.

Prosecutors have in the past vehemently denied that the investigation was biased and have said in filings that stabbing victims have not been cooperative.

The Guardian previously interviewed two victims who were injured, then pursued by police – Cedric O’Bannon, a black journalist and stabbing victim who ultimately was not charged, and Yvette Felarca, a well-known Berkeley activist whose case is moving forward on Thursday. Previous records also revealed that police had worked with the neo-Nazi groups to target the anti-racist activists.

The records disclosed this week provided new details about six other stabbing and beating victims who were treated as suspects by police after the rally in Sacramento, which was organized by a neo-Nazi group called the Traditionalist Worker party (TWP) and an affiliated California group, the Golden State Skinheads.

Lawyers analyzed more than a hundred police reports, finding that the California highway patrol (CHP) investigated 22 men affiliated with TWP and recommended no charges for 17 of them, including some who police said were holding knives.

For every anti-fascist protester police could identify, however, law enforcement pursued charges, including against people who were not accused of any violence and were simply attending the counter-demonstration alongside other activists, defense attorneys wrote. Those activists were accused of “unlawful assembly”.

One anti-fascist was stabbed in the abdomen by an “unknown TWP affiliate”, according to a CHP report, which included graphic images of the protester’s bloody injuries. But because this individual had a “wooden skateboard” that could be used as a “deadly weapon” as well as a “black bandana” to conceal their face, police recommended more than a dozen criminal charges, including conspiracy, assault, rioting, and disturbing the peace. This person was questioned by police at a hospital.

For another victim, stabbed in the pelvis, which was also documented in photos, CHP said it was “unknown” how the individual was injured. The protester’s “medical condition” was severe enough that he was unable to give a statement to police at the hospital. Still, CHP recommended nine charges against him, because he had allegedly “swung his fists” at a TWP member, was “not acting in self-defense”, and had brought a bandanna.

Cedric O’Bannon, a California activist and citizen journalist who was stabbed at the protest. Photograph: Robert Gumpert/The Guardian

Another activist suffered a “broken left wrist, two skull fractures, a fractured left cheekbone, and bruises to the left side of his face and head”, according to the police’s own account. But CHP wrote that he should face a wide range of charges, including assault, because he was observed “joining in a riot where [he] sustained injuries”.

TWP also said this individual should be charged with “false imprisonment”, because he “caused TWP affiliates to retreat back to their vehicle out of fear of further injury”.

Of the eight who suffered serious injuries and then faced potential charges, only Felarca’s case was ultimately prosecuted.

Still, the pursuit of charges against stabbing victims was stunning, said Mark Airgood, an activist working with the defense team.

“I found it reprehensible and shocking,” he said. “It’s transparent … that police targeted anti-fascists for prosecution.”

Ultimately, the Sacramento district attorney’s office decided to charge one man police linked to the white nationalist side, William Scott Planer. He was accused of striking a protester on the head with a “wooden stick”.

In addition to Felarca, two anti-fascists are facing charges in the case advancing this week – Porfirio Paz, who is 21 years old, and Michael Williams, 58. The CHP investigations delved into extensive details about social media activity related to the two of them, noting their reported involvement with the Brown Berets, a Chicano rights group.

In Williams’s report, the CHP said the group was known for its “deeply held belief that they are the original peoples of the region and work for civil rights of ‘chicanos’,” adding: “[Williams’s] continuous presence at protests, community projects and events both before and after the … riot are consistent with known philosophies, tactics, techniques and/or procedures and indicate a strong commitment to the furthering the goals of Brown Beret movement.”

Paz, who is Mexican American and Native American, according to his lawyer, was “observed wearing a black beret” and other black clothing, police wrote. CHP also referenced his participation in an indigenous-led event raising awareness about the chinook salmon, which is threatened with extinction. The report included a Facebook photo of him with his fist raised next to other activists holding signs that said, “Water is life” and “Let the river be a river”.

Police cited as further evidence the fact that Paz at a later date allegedly had an “antifascist” sticker with him.

“I find it concerning to think that the government wants to conduct inquiries into people’s political persuasions and has it influence their decisions as to who to prosecute and how to prosecute,” said Linda Parisi, Williams’s attorney.

Ronald Cruz, another defense lawyer, said in a statement that police “considered it a crime simply for being at a protest against fascists”. His court filing added: “This call for arrests of anti-fascists was all-encompassing and included individuals who the CHP alleged did nothing more than rally alongside other individuals who opposed the fascists.”

Williams and Paz were both accused by police of committing assaults with “sticks” during the fighting.

CHP declined to comment. The Sacramento district attorney’s office did not respond to a request for comment.

In one earlier filing, prosecutors said the charges were based on evidence, adding: “No one is beneath the protection of the law, no matter how repugnant his or her rhetoric or misguided his or her ideals.”