A class-action civil rights lawsuit filed late Tuesday alleges that more than a dozen St Louis-area municipalities are engaged in the discriminatory and unconstitutional practice of jailing people for unpaid debts in order to raise state revenue, a situation the suit says amounts to a system of modern-day “debtors’ prisons” that primarily affects poor residents of color.

The suit alleges a widespread system of local government abuse that targets primarily black communities, where poor people are routinely imprisoned because they cannot escape from the burden of fees generally associated with petty offenses.

“Defendants have created or revived de facto debtors’ prisons, using them as a tool tocow poor people into financing municipal government,” the suit states. “Such flagrant abuse is not consistent with the values this country holds dear, with the rule of law, or with the constitutional guarantee of due process.”

The suit was launched on the second anniversary of the police killing of the unarmed black teenager Michael Brown, whose 2014 death sparked major protests in Ferguson, Missouri, and beyond, and reignited a national debate about the bias against minorities prevalent in the US justice system.

That case led to increased scrutiny of St Louis County, a jurisdiction made up of a maze of 90 constituent municipalities – including Ferguson – 81 of which are responsible for their own police and court systems.

In the wake of Brown’s death, the justice department in 2014 launched a federal investigation into Ferguson’s criminal justice system, culminating in a damning assessment in March 2015, which decried an overly punitive approach to policing that largely affects residents of color.

The report also singled out the legal system for its reliance on generating revenue from mostly poor citizens as one of the key impediments to serious reform. “Ferguson’s law enforcement practices are shaped by the City’s focus on revenue rather than by public safety needs,” the justice department report stated.

Tuesday’s suit describes how this revenue-focused policing model has continued apace in St Louis County’s neighboring municipalities.

All of the plaintiffs in the case were jailed for failure to provide a cash payment related to a fee or fine, the suit says.

In 2015, the municipalities listed in the suit issued an average of 1.7 arrest warrants per household, and one arrest warrant for every adult, mostly for “minor municipal ordinance violations, like traffic tickets”.

The suit points to a “direct correlation between the revenue that a particular municipality raises through fines and fees and the population of black and impoverished residents living in that municipality”.

The justice department has decried the practice of using unpaid fees as a means of imprisoning indigent defendants, and not only in its Ferguson report.

In March, it sent a letter to court administrators and police officials in all 50 states, warning local court systems and police departments against the unlawful use of fees and fines and trapping poor defendants in an escalating cycle from which they may not escape.

Without directly threatening federal action, the letter also noted that local court systems that receive federal money risked violating the Civil Right Acts of 1964 if “they unnecessarily impose disparate harm on the basis of race or national origin”.

“The consequences of the criminalization of poverty are not only harmful – they are far-reaching,” said attorney general Loretta Lynch at the time. “They not only affect an individual’s ability to support their family, but also contribute to an erosion of our faith in government.”

The suit follows a similar one launched last year against the municipalities of Ferguson and Jennings by ArchCity Defenders and two other civil rights groups.

Last month, the small city of Jennings, Missouri, ended up settling that lawsuit, agreeing to pay some $4.7m to approximately 2,000 residents, the majority of them poor and black.

“In terms of a class-wide settlement agreement, this is the largest on a case like this,” said Michael-John Voss, cofounder of ArchCity Defenders, the St Louis not-for-profit group representing the plaintiffs.

Voss said his organization was hoping to build on that result.

“I think it sets a precedent for other towns in this region that they’re on notice,” Voss said.

The new legal action was brought by ArchCity Defenders and Arnold & Porter, a national law firm, on behalf of 12 plaintiffs against 13 municipalities adjacent to Ferguson, Missouri, in St Louis County.

A separate lawsuit filed on Tuesday, which was also initiated by ArchCity Defenders along with the St Louis-based Dowd & Dowd law firm, challenges how law enforcement handled charges against protesters.

That legal action, also filed in federal court in Missouri, is asking for $20m in compensation and an acknowledgment that the city of Ferguson engaged in the malicious prosecution of four individuals who they say peacefully protested at a vigil just two days after Michael Brown’s 2014 death.

The city subsequently spent thousands of dollars prosecuting the cases, according to the suit, even after the justice department’s 2015 report.

In March of this year, a month after a justice department lawsuit against the city to force its hand on criminal justice reforms, Ferguson agreed to settle with the federal government under a reform agreement called a “Consent Decree”.

But the second suit released on Tuesday asserts that that agreement came with a carve-out that it would not affect some cases that had already been under consideration.

In its March 2015 report, the justice department described how the “failure to comply” ordnance of Ferguson – which allowed the city to arrest many protesters after the shooting death of Brown during protests even if they were they were peaceful – was often applied in an unconstitutional and racially discriminatory manner.

But the lawsuit argues that while the Consent Decree required Ferguson to address the “use of arrest in retaliation for exercise of protected speech, it did not require Ferguson to dismiss existing charges against those, like Plaintiffs, who had been arrested on frivolous and retaliatory ‘failure to comply’ charges”.

Jasmine Woods, the lead plaintiff in that lawsuit, was acquitted of all charges in April 2016 along with her three co-plaintiffs.

“I felt like someone should be held accountable,” Woods said of the lawsuit.

“I really felt like I had a strong voice then,” she added, referring to the night two years ago when she was arrested for attending the vigil in Ferguson. “I feel like they’ve kind of damaged that voice because I don’t feel like I have the freedom to go out like I did that day.”

Since her arrest, Woods described how difficult it has been to get jobs, and the adverse toll the day has had on her family, her livelihood, and even her passion for criminal justice, the topic of her undergraduate degree at nearby Harris Stowe State University.

She said it felt like the authorities “put a bad aura on my name”.

“We see this as a larger problem in the United States and there is just now becoming some discussion about when are we going to hold the key players in this system that abuse people accountable,” said Voss of Woods’ case. “And I think that our lawsuit is a step in that argument.”