By the CNN Wire Staff
(CNN)-- The U.S. Justice Department plans to file a civil lawsuit against Maricopa County, Arizona, and Sheriff Joe Arpaio over civil rights violations.
In a letter sent Wednesday to an attorney for the Maricopa County Sheriff's Office, Assistant U.S. Attorney General Thomas Perez writes that the county's failure to address racial discrimination and other violations found by the federal government in December will go to litigation.
The sheriff's policies are unconstitutional and in violation of federal law, and compliance "cannot be secured through voluntary means," the letter said.
As a result, the Justice Department will file suit against the county, the sheriff's office and Arpaio.