A man named by authorities as a figure in the drug ring kidnapping of a 6-year-old Nevada boy was indicted on an immigration charge Wednesday by a federal grand jury, the U.S. attorney's office said.

Jose Luis Lopez-Buelna, 48, was charged with being a deported alien found unlawfully in the United States, said Natalie Collins, spokeswoman for U.S. Attorney Gregory Brower. No arraignment date was immediately set.

The charge keeps Lopez-Buelna in federal custody following his release from state custody last week. He spent more than a week in the Clark County jail following his Oct. 17 arrest by police investigating the Oct. 15 abduction of first-grader Cole Puffinburger.

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The boy became the focus of Nevada's longest Amber Alert and an intensive search in neighboring states before he was found unharmed late Oct. 18 on a Las Vegas street.

Las Vegas police characterized the abduction as a message from "Mexican nationals" and methamphetamine traffickers to the boy's grandfather, Clemens Fred Tinnemeyer.

Tinnemeyer, 51, and his girlfriend, Terri Lynn Leavy, 42, were arrested last month in Southern California and are being held by federal authorities in Las Vegas pending a preliminary hearing this month on federal racketeering charges.

Federal prosecutors allege Tinnemeyer stole millions of dollars in drug money from a U.S.-Mexico smuggling operation using a hidden compartment in a recreational vehicle.

Lopez-Buelna is named in the complaint against Tinnemeyer and Leavy as one of two men from whom Tinnemeyer and Leavy allegedly stole $300,000 to $400,000 in drug money.

Police have identified Lopez-Buelna as an illegal immigrant and convicted drug trafficker who was deported to Mexico in 2003.

No one has been charged in the abduction, and a police representative said Wednesday that a fourth "person of interest" was still being sought. He has been identified as Jesus Gastelum, 35, a Mexican citizen who also used the name Ferdinand Gastelum.