DENVER — The U.S. Department of Justice on Thursday announced it had sued Joe Arpaio, the controversial sheriff of Maricopa County in Arizona, for failing to turn over documents in an investigation of whether his aggressive operations against illegal immigrants had violated civil rights.

The litigation came two months after a Justice Department lawsuit halted a tough new Arizona immigration law, which Arpaio strongly supported. The new lawsuit is unrelated to the immigration law and stems from an investigation into the sheriff’s immigration enforcement operations. The department said it was the first time in 30 years a police agency had not cooperated in a civil rights probe.

“”The actions of the sheriff’s office are unprecedented. It is unfortunate that the department was forced to resort to litigation to gain access to public documents and facilities,”” said Thomas E. Perez, assistant attorney general for the civil rights division, in a statement.

Arpaio’s attorney said he could not comment on the lawsuit until he had time to review it.

For more than three years, Arpaio has attracted praise as well as condemnation for using his deputies to track down illegal immigrants. The most high-profile example is his so-called “”sweeps,”” during which deputies flood immigrant-heavy neighborhoods, stop people for minor infractions such as driving with a broken taillight and check their immigration status. The tactics have made Arpaio popular in Arizona, the main gateway for illegal immigrants into the United States, but also have drawn widespread complaints that he unfairly targets Latinos.

Last year, the Obama administration withdrew from part of an agreement that had allowed Arpaio’s deputies to enforce federal immigration laws. The move made little difference — the sheriff says he can use state laws against illegal immigrants and has continued his operations. He has also touted the fact that federal civil rights investigators have yet to charge him with anything, while simultaneously announcing he was not cooperating with them and barring them from his facilities.

In the lawsuit, the Department of Justice said it asked for 51 different sets of documents in March 2009, shortly after launching the probe. Arpaio’s office provided only 11 pages and had not handed over any others. His office also would not let investigators tour the county jail or other sheriff’s facilities. Arpaio previously said he had no legal obligation to give the Justice Department other material and dismissed the probe as politically motivated.

Arpaio’s agency also has been sued by a coalition of private civil rights lawyers who have complained that it has not provided them with documents. A federal judge earlier this year found the sheriff’s department had destroyed documents on the sweeps that the plaintiff’s attorneys were legally entitled to review and sanctioned the agency.

Arpaio is also under investigation by a federal grand jury for alleged abuse of power in a separate probe. He has denied those allegations.