WASHINGTON (CNN) -- The Supreme Court agreed Monday to examine whether prosecutors can aggressively prosecute illegal immigrants for identity theft if they didn't know the documents they were given belonged to someone else.
The Supreme Court has agreed to grapple with the issues of identity theft and illegal immigration.
The justices announced they will hear arguments in the appeal of a Mexican national arrested in a government work site raid in the Midwest. A ruling is expected by June.
At issue is whether people who use fake IDs to obtain work in the United States but did not know the documents belonged to someone else can be convicted of "aggravated identity theft."
Stealing personal identification such as Social Security numbers is illegal, but federal courts around the country are divided over how to treat people who buy them on the black market. Federal law states that for aggravated identity theft to occur, it must be proved that a person "knowingly transfers, possesses, or uses, without lawful authority, a means of identification of another person."
Many criminals steal a person's identification to empty his or her bank account or falsely obtain loans or credit.
Lawyers for the detained illegal immigrants say their clients simply used numbers picked "out of thin air" that happened to belong to another person. They used the numbers only to obtain work, not steal to money, the lawyers said.
The Justice Department argues its prosecutors need not prove "knowledge" that the documents belonged to someone else instead of being fabricated.
The difference could mean an additional two years in federal prison under an enhanced sentence. Most workers with false papers serve only a few months behind bars, and many are then deported.
At stake is the government's crackdown on undocumented workers, most of whom must rely on fake IDs to obtain employment. Read a report from the front lines of the immigration debate
The case before the justices involves Mexican immigrant Ignacio Flores-Figueroa, who worked at a steel plant in East Moline, Illinois. He was arrested with phony Social Security and alien registration cards that had been assigned to someone else. He admitted obtaining the documents but said he did not know they were someone else's. He was convicted and sentenced to 75 months in prison.
The court did not act on a similar appeal from a Mexican national who was arrested during a raid on a meat processing plant in Iowa, the largest criminal workplace enforcement operation in U.S. history. Nicasio Mendoza-Gonzalez was among 389 people arrested, most of whom were given five months in prison.