(CNN)-- The U.S. Justice Department filed a civil lawsuit Thursday against Maricopa County, Arizona, and Sheriff Joe Arpaio over civil rights violations.
"At its core, this is an abuse of power case involving a sheriff and sheriff's office that disregarded the Constitution, ignored sound police practices, comprised public safety, and did not hesitate to retaliate against perceived critics," said Assistant U.S. Attorney General Thomas Perez.
The Justice Department had delivered in December a report with findings of civil rights violations and sought to fix them through a negotiated settlement with Maricopa County and its sheriff's office. Those talks broke down in February over Maricopa's refusal to consider any agreement that involved an independent monitor, Perez said.
"Attempts to forge solutions to address the serious civil rights and public safety concerns have proven elusive," Perez said.
According to the civil complaint, the sheriff's office has a pattern of discrimination against Latinos, which includes racial profiling, unlawful detention and searches, and unlawful targeting of Latinos during raids.
The complaint also alleges at Maricopa detention officers discriminated against Latino prisoners in the jail. The targets are often prisoners who don't speak English well, Perez said. The jailers would give orders only in English, and when the prisoners didn't understand, they would place an entire area of the jail on lockdown for disobedience.
"This incites obvious and unwarranted hostility toward the inmates, potentially placing prisoners and officers alike in harm's way," Perez said.
Finally, the complaint recounts a number of cases were Sheriff Arpaio and his office retaliated against perceived enemies. These included judges, lawyers and community leaders who were critical, or perceived to be critical of Maricopa policies.
"Nobody is above the law, and nobody can misuse the legal process to silence those with different opinions," Perez said. "Leadership starts at the top, and all of the alleged violations outlined in the complaint are the product of a culture of disregard for basic rights within MCSO that starts at the top and pervades the organization."
The December letter said detention officers in Arpaio's jail invoked offensive slurs and profanities against Hispanics, calling them "wetbacks," "Mexican bitches" and "stupid Mexicans."
Arpaio has denied any discrimination, and one of his attorneys called the Justice Department investigation a "witch hunt."