An illegal immigrant awaiting a deportation ruling has been charged with killing a nun and critically injuring two others in a drunken driving crash that has sparked criticism of how immigration enforcement is handled.

A local official in the Virginia suburb where the crash happened and a congressman from another state have criticized federal officials for not removing the suspect from the country after previous arrests, and even U.S. Homeland Security Secretary Janet Napolitano questioned why his deportation was taking so long. A spokeswoman for the nuns' order, meanwhile, said they're upset that the tragedy is being politicized.

Twenty-three-year-old Carlos Martinelly Montano, who police say is illegally in the country, is charged with drunken driving, involuntary manslaughter and felony driving on a revoked license after the accident on Sunday in Virginia's Prince William County. Montano was arrested two times before and charged with drunken driving, according to county police, and has also been arrested in separate incidents for other traffic-related offenses. Police say Montano, who is from Bolivia, was turned over to Immigration and Customs Enforcement after at least one arrest, and a prosecutor said he knew of at least one other occasion he'd been referred to immigration officials.

The Department of Homeland Security said Tuesday that Montano was released in 2008, pending an immigration judge's review of his case. As of August 2010, a judge had not ruled on his deportation.

U.S. Homeland Security Secretary Janet Napolitano called the crash a "terrible thing" when asked about the incident during an unrelated news conference at D.C. police headquarters Tuesday. Napolitano said she immediately asked officials to look into the situation.