UPDATE: Arpaio formally charged with criminal contempt-of-court

U.S. Department of Justice attorneys on Monday filed proposed criminal contempt charges against Maricopa County Sheriff Joe Arpaio, accusing him of intentionally violating a federal judge's order by arresting undocumented immigrants without evidence they had broken state law.

The proposed charges were requested at a hearing last week by Federal Judge Susan Bolton, who is overseeing Arpaio's criminal case. Bolton must sign off on the charges.

Arpaio's attorney has said the sheriff will plead not guilty. Unlike other criminal defendants, Arpaio will not be arrested or be required to personally enter a plea in court.

The charges carry a sentence of up to six months in jail. Legal experts have said that given Arpaio's age -- he's 84 -- and lack of a criminal record, it's unlikely he would serve any time if convicted.

The Justice Department filing comes as early voting begins in Arizona. Arpaio is running for a seventh term in office against Democrat Paul Penzone.

READ: Proposed criminal charges against Sheriff Joe Arpaio

The proposed criminal contempt charges stem from Federal Judge Murray Snow's preliminary injunction in December 2011, barring Arpaio and the Maricopa County Sheriff's office "from enforcing federal immigration law or from detaining persons they believed to be in the country without authorization but against whom they had no state charges," according to the DOJ's court filing.

Federal prosecutors say Arpaio violated that order.

Judge Snow referred the case to prosecutors after concluding in August that Arpaio had committed criminal contempt.

The charges stem from Arpaio's 9-year-old racial-profiling case before Judge Snow. Snow issued a landmark ruling in May 2013 that the sheriff violated the constitutional rights of Latino citizens by racially profiling them.

In response to the imminent charges, the sheriff said in a statement last week: "It is clear that the corrupt Obama Justice Department is trying to influence my reelection as Sheriff of Maricopa County ... It is a blatant abuse of power."