Being convicted of killing a couple of people didn't get Mario Montalban-Ramirez deported. Being passed out drunk at a bus stop in St. Paul probably will -- after he serves a term in federal prison.

Montalban-Ramirez, 62, pleaded guilty Monday to illegally entering the United States after deportation, a crime that could put him behind bars for 20 years before another likely deportation. Such a sentence would be the most significant time he has served over three decades of offenses in Minnesota and elsewhere.

He will be sentenced at a later date.

Officials with U.S. Immigration and Customs Enforcement (ICE) say that cracking down on convicted felons who are in the country illegally is a high priority. ICE agents were checking the Ramsey County jail roster last December when they discovered a man who has repeatedly slipped through the cracks.

The man who passed out with a nearly empty bottle of vodka in his coat pocket was not just any homeless drunk. Montalban-Ramirez was convicted of manslaughter in Illinois in 1982, convicted of murder in Texas just two years later and had three previous deportations to his native Mexico -- in 1996, 1997 and 2003.

Yet, despite other arrests since his latest deportation, Montalban-Ramirez -- who has often gone by the name of Oscar Yturria -- has been able to stay here for much of the past two decades.

Federal and local officials acknowledged in January that they don't know how he has been allowed to stay despite so many run-ins with the law. Prosecutors admit that many deportees quickly return to the United States, drawn by families and jobs and lives built here over the years -- despite criminal records.

Officials are turning more to federal illegal-reentry prosecutions and the longer prison terms they carry to at least slow the revolving door.

ICE officials won't comment on Montalban-Ramirez, a short man with a full head of white hair who was living at a mission in St. Paul when he was arrested. He seemed far removed from the man convicted of violence more than 30 years ago.

On Monday, he stood before U.S. District Judge Patrick Schiltz, politely answering questions. When Schiltz asked if he'd had anything to drink in the past 24 hours, Montalban-Ramirez replied through an interpreter: "I don't know when, no."

He said he was taking medications for high blood pressure, for his kidneys and for constipation. Schiltz determined that Montalban-Ramirez was clear-headed enough to enter a guilty plea.

Montalban-Ramirez admitted he couldn't remember being arrested in December. He does remember waking up in the Ramsey County jail, he told his attorney, Katherian Roe.

Jeanne Cooney, spokeswoman for the U.S. attorney's office, said her office now prosecutes about 10 cases per month of people illegally reentering the country after previous deportations -- compared with almost none before 2008.

James Walsh • 612-673-7428