Large law firms are helping lead a wave of litigation that has emerged since George Floyd's killing in Minneapolis in late May, alleging excessive force by police officers at protests and other acts of police violence.

The ACLU of Minnesota and attorneys with Fish & Richardson are teaming up for a class action lawsuit filed Tuesday against Minneapolis and city police officials over injuries suffered by protesters demonstrating in the wake of Floyd's death. Meanwhile, firms including Debevoise & Plimpton, Snell & Wilmer and Perkins Coie are involved in a series of lawsuits filed in connection to the recent use of federal law enforcement in Portland, Oregon.

The Minneapolis lawsuit was filed in the U.S. District Court of Minnesota on behalf of four named protesters and others who were injured during the protests that swept the city starting in late May.

"Historically, law enforcement in Minneapolis specifically, and Minnesota more generally, have attempted to suppress the right of its citizens to assemble peacefully. Recently, they have been and are actively suppressing this right by exercising unnecessary and excessive force against protesters who gathered to express their outrage at the murder of George Floyd at the hands of the Minneapolis Police Department," the complaint reads. "This unnecessarily forceful treatment of protesters, at the expense of proper constitutional protections, casts a pall over future protests and cannot continue."

The lawsuit targets the city and police authorities, including Minneapolis Chief of Police Medaria Arradondo, "for retaliating against persons engaging in First Amendment-protected activity; for applying excessive force; and for violating procedural due process rights by firing chemical irritants and other less-lethal munitions for the purpose of intimidation without a constitutionally-sufficient warning."

Ahmed Davis, a principal at Fish & Richardson's Washington, D.C., office who is leading the lawsuit, said in an interview the firm has previously worked alongside the ACLU's Minnesota chapter on other pro bono matters and the organization reached out to the practice to file the complaint.

He said while Fish traditionally focuses on intellectual property law, the firm has strengthened its pro bono practice in recent years and amplified its racial justice work in the wake of Floyd's killing. Fish recently announced a "racial justice initiative" as part of those efforts; Davis said Tuesday's lawsuit is not necessarily part of that project, "but it certainly speaks to what that initiative is about."

"There's something different about being able to invest the firm's resources and its abilities in assisting everyday people with things that matter to everyday people, and addressing larger societal issues in the firm," Davis said.

The new Minneapolis lawsuit describes lasting injuries the named individuals suffered since participating in protests. The complaint states that Nekima Levy Armstrong and Marques Armstrong, a married couple, were teargassed by officers at a May 27 protest, and "and are still experiencing residual effects from the tear gas."

"Since the MPD sprayed her with tear gas, Plaintiff Nekima Levy Armstrong has had lingering lung issues and her voice has not returned to full strength. She routinely uses her voice as an instrument to lead chants at protests and the damage to her voice as a result of the tear gas has limited her ability to do that," the lawsuit reads.

The other named individuals, Terry Hempfling and Rachel Clark, were both teargassed and struck by less-lethal munition such as rubber bullets fired by Minneapolis police officers, according to the complaint. The lawsuit includes images of their injuries.

The ACLU of Minnesota last month worked with firms Fredrikson & Byron and Apollo Law for a class action suit on behalf of reporters covering the protests, claiming officers were targeting and attacking the media in violation of the Constitution.

Several lawsuits have also been filed in connection to the use of federal law enforcement in Portland. The ACLU of Oregon sued the Trump administration alleging attacks on reporters in Portland with firm BraunHagey & Borden, and filed a separate complaint on behalf of Portland street medics alongside attorneys at Perkins Coie. Oregon Attorney General Ellen Rosenblum also sued the administration, but a federal judge denied her bid for a temporary restraining order against federal authorities.

Snell & Wilmer attorneys are also behind another Portland complaint, and on Monday lawyers with Debevoise & Plimpton and Perkins Coie filed a federal complaint in Washington, D.C., trial court on behalf of women and women groups at the protests, including the recently formed organization "Wall of Moms."

While Tuesday's lawsuit does not address federal law enforcement, Davis pointed to the complaint as a way to address the dangers of law enforcement using excessive force. He noted that while three of the named plaintiffs are experienced protesters, Clark was a first-time demonstrator, and even seeing force used against other protesters can have a chilling effect.

"I think that this suit and others like it that may well be coming are very important, because what we see happening in Portland, in Seattle and in many other cities is emblematic of a very disconcerting trend in this country that seeks to quell free speech," Davis said. "And if we're not careful, if we don't address it head-on and call it what it is, we could find ourselves in a society in the not-too-distant future that doesn't look anything like the America that our forefathers envisioned and that many have fought and died for."