The Department of Justice plans to sue Maricopa County, Arizona Sheriff Joe Arpaio for civil rights abuses, including racial profiling against Latinos.

The legal action follows the Justice Department's unsuccessful attempt to broker a compromise in which Arpaio would work with federal officials to reform his department. A comprehensive federal investigation of the Maricopa County Sheriff's Office found a pattern of unconstitutional policing and a widespread disregard for basic legal and constitutional obligations. The report concluded that officers discriminated against Latinos with unlawful stops and arrests, stopping their vehicles at a far higher rate, often conducting illegal searches, and charged that officials mistreated Latino inmates.

MCSO's systematic disregard for basic constitutional protections has created a wall of distrust between the sheriff's office and large segments of the community, which dramatically compromises the ability to protect and serve the people, Thomas E. Perez, assistant attorney general for the Justice Department's Civil Rights Division, said in December. The problems are deeply rooted in MCSO's culture and are compounded by MCSO's penchant for retaliation against individuals who speak out.

But Arpaio defied federal authorities, rejecting a court-appointed monitor and saying the agreement the Obama administration sought would undermine his ability to enforce the law. On Wednesday, Perez sent an Arpaio lawyer a letter announcing the government's intent to file a federal lawsuit, according to the Associated Press.

Arpaio has become a highly divisive national figure for his harsh enforcement of immigration laws. Supporters laud him for aggressively targeting illegal immigration in Arizona -- Arpaio calls himself America's toughest sheriff, a title whose origin is unclear but that he wears proudly -- while critics say he is fostering a climate of fear and racially motivated persecution.

After announcing the findings of the civil rights probe, Perez said investigators had uncovered a pervasive culture of bias in the Maricopa County Sheriff's Department. He told reporters the investigation took longer than anticipated because the department was often unwilling to cooperate.

What is unique about the findings here is what appears to be at the highest levels of the organization, and that's an issue -- when we were peeling the onion -- that began to jump out at us more and more and more, Perez said.

The investigation also expanded to address allegations that, in his zeal for targeting undocumented immigrants, Arpaio had neglected hundreds of potential sex crimes cases.

In addition to coming under scrutiny for allegedly abused Hispanics, Arpaio has attracted a criminal investigation over accusations that he had used his power to intimidate and silence public officials who were critical of his tactics. Several prominent Arizona officials recently exhorted Attorney General Eric Holder to file charges or drop the probe.