Updated

Federal prosecutors filed identity theft charges on Friday against the woman accused in a school bus crash that killed four students.

Olga Marina Franco del Cid, 24, of Minneota, was already charged in state court with four counts of criminal vehicular homicide.

The new charges accuse her of giving authorities a false name and Social Security number after the crash Feb. 19, when four students were killed when a van she drove crashed into their school bus near Cottonwood in southwestern Minnesota. She was charged with two counts of aggravated identity theft and two counts of false representation of a Social Security number.

Prosecutors filed the same federal charges against her live-in boyfriend, Francisco Sangabriel-Mendoza, 29, also of Minneota, who prosecutors say was the registered owner of the van. A warrant was issued for his arrest, and authorities asked anyone who knows his whereabouts to call the Immigration and Customs Enforcement toll free hot line at 1-866-347-2423.

Franco's attorney, Manuel Guerrero of St. Paul, declined comment on the new charges, saying he hadn't seen them. Franco did not immediately return a message left at the Lyon County Jail in Marshall.

Both of Franco and Sangabriel-Mendoza face maximum potential penalties of five years in prison on each false representation count and two years on each identity theft count.

Right after the crash, Franco identified herself as Alianiss Nunez-Morales. But immigration investigators found the real Nunez-Morales in Connecticut. She told them her purse and identification documents were stolen more than six months ago when she was living in Puerto Rico, according to an ICE affidavit.

The affidavit alleges Franco used Nunez-Morales' Social Security number to obtain a Minnesota identification card, an ID that is not a driver's license. Franco allegedly was not licensed to drive in Minnesota. She also allegedly gave the Social Security number at two Minnesota companies where she worked.

When ICE agents searched her home in Minneota last Friday, they found a Guatemalan birth certificate, a certified Guatemalan ID card for Franco, correspondence to and from Guatemala in the name of her parents, and numerous receipts showing money transfers to her mother in Guatemala, the U.S. Attorney's Office said in a news release.

Authorities earlier said Franco is in the United States illegally.

The complaint against Sangabriel-Mendoza alleges he used the Social Security number of a Puerto Rican man to get work at two Minnesota companies.

An ICE affidavit alleges Sangabriel-Mendoza is a Mexican citizen who's in the U.S. illegally. It says he married a U.S. citizen in 2004, but they divorced, so his petition for permanent residency was denied last September and he was given 30 days to leave the country.

During the search last Friday, ICE agents also found the Puerto Rican man's birth certificate, as well as other documents, including a Minnesota driver's license, a Mexican passport and a Mexican birth certificate in Sangabriel-Mendoza's name.

"ICE aggressively investigates those who commit identity theft to circumvent our nation's immigration laws," Claude Arnold, special agent in charge of ICE's Office of Investigations in St. Paul, said in a statement. "... Today's charges reflect ICE's commitment to investigating those who assume other people's identities to skirt the law."