Federal authorities said Wednesday that they plan to sue Arizona sheriff Joe Arpaio and his office over allegations of civil rights violations, including the racial profiling of Latinos.

The U.S. Justice Department has been seeking an agreement requiring Arpaio’s office to train officers in how to make constitutional traffic stops, collect data on people arrested in traffic stops and reach out to Latinos to assure them that the department is there to also protect them.

Arpaio has denied the racial profiling allegations and has claimed that allowing a court monitor would mean that every policy decision would have to be cleared through an observer and would nullify his authority.

DOJ officials told a lawyer for Arpaio on April 3 that the lawman’s refusal of a court-appointed monitor was a deal-breaker that would end settlement negotiations and result in a federal lawsuit.

The “notice of intent to file civil action” came Wednesday from Assistant U.S. Attorney General Thomas Perez in a letter to an Arpaio lawyer.