The Department of Justice filed a 56-page civil lawsuit Wednesday against the City of Ferguson, Mo. alleging that, 18 months after the police shooting of Michael Brown, the city’s police and court system continue to violate black residents’ civil rights.

The suit — a contentious next-step in what has been a months-long negotiation process between federal and city officials over potential reforms — says these “ongoing and pervasive” violations come from the city’s use of law enforcement to generate revenue.

“Residents of Ferguson have suffered the deprivation of their constitutional rights — the rights guaranteed to all Americans — for decades,” Attorney General Loretta Lynch said during a news conference Wednesday in which she was impassioned as she spoke about the urgent need for reform in Ferguson. “They have waited decades for justice. They should not be forced to wait any longer.”

The lawsuit, filed in the U.S. District Court for the Eastern District of Missouri, alleges that Ferguson’s police department and municipal courts engage in an unconstitutional “patterns and practices” of using force without legal justification and “engaging in racially discriminatory law enforcement conduct.”

Federal officials say the civil rights violations stem from the city’s failure to properly train and supervise its law enforcement officers, echoing the findings of the 2014 Justice Department investigation into Ferguson’s police force.

The Justice Department bluntly states in the suit that Ferguson’s focus on revenue is the reason the city’s officials have never changed politics to try and “decrease or eliminate police misconduct, including discriminatory policing, unconstitutional stops, searches and arrests, and the use of unreasonable force.”

While the suit acknowledges that the city has made some reforms since the Justice Department conducted its investigation, it also states that they are insufficient to both eliminate the practices and prevent them from happening in the future.

The lawsuit comes one day after city officials requested several changes to a tentative agreement reached by city and federal negotiators following the Justice Department’s investigation into the city’s police and court practices — which concluded that the city engaged in practices that were racially discriminatory and violated residents’ civil rights.

“Our investigation found that Ferguson’s policing and municipal court practices violate the Constitution, erode trust and undermine public safety,” said Vanita Gupta, the DOJ’s  principal deputy assistant attorney general.

The tentative agreement reached last month was in the form of a 131-page consent decree that, among other things, would establish long-term programs promoting interactions between the police and youths and ensure that officers are provided the training, supervision and support they need to police effectively but also “lawfully and ethically.”

Ferguson’s city council members voted unanimously on Tuesday night to accept the Justice Department’s proposed reforms only if federal officials agreed to seven changes, which included: changing the deadlines in the agreement, not mandating any salary increases for police officers and altering certain fees.

The Justice Department quickly disparaged the city council’s actions as an unfair development after extensive negotiations. Gupta, who heads the department’s Civil Rights Division, vowed that the federal government “will take the necessary legal actions” to reform the city’s courts and policing practices.

A spokesman for Ferguson did not respond to a request for comment about the lawsuit, though in the hours before the suit was announced, city officials had said they were still open to negotiating with the Justice Department.

Under powers granted to the federal government by legislation passed after the police beating of Rodney King in Los Angeles, the Justice Department can force police agencies to undergo reforms if it concludes a department’s current policies permit civil rights violations, and can sue a municipality to force such changes if city officials do not cooperate.

The negotiations stem from the federal investigation into the police shooting of Michael Brown, an unarmed black man whose death prompted nationwide protests, as well as a parallel investigation into the city police force’s “patterns and practices.” The Ferguson probe is one of more than two dozen such investigations into police departments conducted by the Justice Department under the Obama Administration, and the city joins at least two other police agencies currently in litigation.

The Justice Department has launched 67 civil rights investigations of police departments over the last two decades. Despite Justice’s threat to sue police agencies, most police agencies targeted have agreed to the federal demands.

Only one police agency has ever been successful once sued by the Department of Justice over alleged civil rights violations — the 117-officer sheriff’s department in Alamance County, N.C., which beat federal lawyers in court in 2015. The Justice Department has appealed that judge’s ruling.

Officials in Ferguson had continued to defend their decision on Wednesday, as they awaited word on whether the Justice Department would sue, and hinted that despite the city’s declaration that the Justice Department “must accept” the new conditions, they were not issuing them as an ultimatum.

“To be clear, in no uncertain terms are these conditions considered ‘take it or leave it,'” Wesley Bell, a city council member elected last year, said at a news conference Wednesday. “The city of Ferguson is and will be open to continued negotiations with the Department of Justice.” 

Bell also defended the proposed changes, saying that they “maintain the spirit and integrity of the consent decree” while letting Ferguson move forward with needed reforms. This sentiment was echoed by the city’s mayor, who was part of the group negotiating with the Justice Department since last year.

“We strongly believe that this agreement, with the modest changes approved by the council last evening, achieves the goals of this consent decree,” Ferguson Mayor James Knowles III said at the same news conference.

The uproar came two weeks after the city said it reached a proposed agreement with the Justice Department following seven months of negotiations, a deal that city officials have described as the best one available for Ferguson residents.

“Although we did not get everything we wanted in the agreement, we certainly made sure that what was agreed upon, can be implemented in a timely and sufficient manner,” Knowles said in a statement Tuesday.

Ferguson officials say the proposed changes this week come in response to worries shared by residents in community meetings earlier this month. People in Ferguson had expressed concerns about the cost of the deal, with the prospect of increased salaries for police officers and city officials becoming one focal point, and the city argues that the new changes would address concerns.

After the vote Tuesday night, though, federal officials said these new conditions were only going to stretch out the process for residents and officers alike.

“The Ferguson City Council has attempted to unilaterally amend the negotiated agreement,” Gupta said in a statement early Wednesday. “Their vote to do so creates an unnecessary delay in the essential work to bring constitutional policing to the city, and marks an unfortunate outcome for concerned community members and Ferguson police officers.”

The NAACP Legal Defense Fund, one of several civil rights groups that has closely followed the investigation into Ferguson, had called on the city to approve the deal, arguing that worries about funding have long been cited as arguments against civil rights changes.

“We reject this argument out of hand as an affront to democracy,” Sherrilyn Ifill, president of the NAACP’s Legal Defense and Educational Fund, said in a statement. She added: “The Ferguson City Council must approve the proposed consent decree and work diligently and immediately to acquire the necessary funds to protect the lives and civil rights of all its residents, regardless of race.”

Kimbriell Kelly contributed to this report.

[This developing story has been updated. First published: Wednesday, Feb. 10, at 8:38 a.m.]