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Maricopa County Sheriff Joe Arpaio, who rose to national fame with his highly publicized crackdowns on illegal immigrants, is standing his ground against the Justice Department, which is threatening to sue his office, arguing that he has refused to cooperate with a civil rights investigation and that he is not in compliance with federal law.

The Justice Department has been investigating Arpaio's office in Phoenix since March 2009 for alleged discrimination and for unconstitutional searches and seizures. Arpaio says the inquiry is focused on his immigration efforts.

Robert Driscoll, a Washington lawyer representing Arpaio, told FoxNews.com that Arpaio has cooperated and accused the Justice Department of trying to make an example out of Arpaio as the Obama administration seeks to discourage states and local authorities from enforcing their own brand of immigration policy.

"I don't think there's any doubt," Driscoll said when asked whether he believed the investigation is politically motivated. "It's a media game."

Driscoll added that if Arpaio was guilty of racial profiling, there would be evidence.

"Could there be a police operation that is more transparent than Sheriff Arpaio's office?" he said. "There are camera crews, reality shows following him as his deputies round up folks in sweeps. He announces them on TV three days before doing it."

A spokeswoman for the Justice Department declined to comment beyond the letter to Arpaio.

In the letter, Assistant Attorney General Thomas Perez, head of the Justice Department's civil rights division, said the sheriff's office is not turning over material that Perez's lawyers are requesting. More than a year ago, Arpaio's lawyers asked that the Justice Department's Office of Professional Responsibility investigate alleged attorney misconduct regarding the investigation. In his letter to Arpaio's lawyers, Perez said such "unfounded allegations" are not a basis for refusing to cooperate with the Justice Department probe.

In June, the office concluded that no civil rights division attorney at the Justice Department committed professional misconduct or exercised poor judgment in the probe of Arpaio's office.

Perez gave the sheriff's office until Aug. 17 to turn over documents first requested last year in what the department calls an inquiry into claims of discrimination based on national origin.

Arpaio and his legal counsel said a year ago that the sheriff's office would not cooperate with the inquiry.

The office "has continued its unwarranted refusal to cooperate," Perez wrote.

In June, the office supplied a position statement regarding the operation of its jail facilities.

The statement says "nothing at all about the allegations of discriminatory police practices," and includes no agreement to provide access to sheriff's office facilities and personnel, Perez said in the letter to the sheriff department's legal counsel. The letter also said a limited production of accompanying documents fails to respond to the first request for material made 17 months ago.

Title VI of the Civil Rights Act of 1964 prohibits discrimination in federally assisted programs on the basis of race or national origin.

Perez pointed out that the sheriff's office signed contractual assurances under Title VI agreeing to allow examination of relevant records by the Justice Department.

The Title VI implementing regulations require that every application for federal financial assistance be accompanied by an assurance that the program will be conducted in accordance with all requirements.

"It's kind of laughable," Driscoll told FoxNews.com, adding that the Justice Department is probably under pressure from Obama supporters to take action.

The Associated Press contributed to this report.