Ferguson Sued by Justice Department Over Alleged ‘Racial Bias’ in Policing The suit is regarding the city's policing.

 -- The Justice Department has filed a federal lawsuit against Ferguson, Missouri, after the city rejected a deal that would have brought sweeping changes to its embattled police department, which allegedly engaged in "racially discriminatory policing."

The lawsuit, announced Wednesday by Attorney General Loretta Lynch, alleges a pattern or practice of law enforcement conduct that violates the First, Fourth and Fourteenth Amendments, as well as federal civil rights laws and says the citizens there "have waited decades for justice."

"The residents of Ferguson have waited nearly a year for their city to adopt an agreement that would protect their rights and keep them safe," Lynch said. "They have waited nearly a year for their police department to accept rules that would ensure their constitutional rights ... They have waited decades for justice. They should not be forced to wait any longer."

Ferguson came under the national spotlight after a city police officer fatally shot unarmed teenager Michael Brown in August 2014. Officer Darren Wilson was never charged in the shooting, but a Justice Department investigation into the Ferguson police department found what Lynch called "systemic and systematic" racial bias within the force's policing practices.

After the results of that investigation were announced last year, the Justice Department began "painstaking negotiations" lasting 26 weeks, seeking to reach a deal that would address the Justice Department's findings, according to Lynch. An agreement was reached weeks ago, but last night the Ferguson City Council "rejected" the deal "approved by their own negotiators," said Lynch, calling the move "extremely unfortunate" and "profoundly disappoint[ing].

"I think that the city of Ferguson had a real opportunity here to step forward, and instead they’ve chosen to turn backwards," Lynch added. "They’ve chosen to live in the past, and they’ve chosen to adopt a means of really ignoring the voices of their citizens, they’re choosing to ignore the complaints of their citizens."

Ferguson leaders expressed concern that the agreement reached would cost the city up to $3.7 million in the first year alone.

Nevertheless, the failure to reach final agreement left the department "no further choice" but to file suit, said Lynch, whose department is now urging a federal judge to compel a litany of changes within the Ferguson police department.

The lawsuit filed today lays out much of what the department detailed in its 104-page report last year.

According to the Justice Department, from October 2012 to October 2014, African Americans were more than twice as likely to be searched, to receive a citation or to be arrested, than other stopped individuals. In addition, of all incidents from 2010 to August 2014, African Americans accounted for 88 percent of all incidents in which a Ferguson police officer reported using force; and while African Americans make up 67 percent of Ferguson’s population, they made up more than 90 percent of all charges involving "manner of walking in roadway," "failure to comply," "resisting arrest," and "disturbing the peace."

"The city and residents of Ferguson deserve what every American is guaranteed under the Constitution: the right to be free from excessive force, from unconstitutional stops [and] from unconstitutional arrests," Lynch said during her announcement today. "We intend to aggressively prosecute this case and we intend to prevail."

The City of Ferguson said it is aware of news reports about the expected suit but had no immediate comment.

City Councilman Wesley Bell declined comment. "Our [lawyers] are currently reviewing the DOJ's filing and we will respond at the appropriate time," Bell said.

ABC News' Geneva Sands and Michael DelMoro contributed reporting.