MIAMI - The reputed kingpin of a violent Colombian cartel blamed for smuggling cocaine worth $10 billion to the United States was flown aboard an FBI plane to Miami yesterday to face a 12-count federal indictment.

Diego "Don Diego" Montoya, described as head of the North Valley Cartel, could spend at least 20 years in prison if convicted on charges of drug trafficking, money laundering, obstruction of justice, and witness retaliation by murder.

Montoya, who did not yet have a U.S. lawyer after his extradition, was being held without bail awaiting an initial court appearance Monday.

Under his leadership, the North Valley Cartel in the mid-1990s become Colombia's dominant cocaine-smuggling organization, taking over from the Cali cartel whose leaders also were prosecuted in Miami. At its height, North Valley controlled about 60 percent of Colombia's cocaine trade, authorities said.

U.S. Attorney R. Alexander Acosta said the extradition of Montoya had further crippled the cartel. Most of the Colombian cocaine trade is now split among smaller groups, with much of the profits and violence moving to Mexican-run groups.

"I do think we're seeing a splintering and a dismantling of the cartel," Acosta said. "But I think it would be premature to declare victory, because others are stepping in to fill the void."

Montoya, the last of Colombia's major fugitive drug lords, was on the FBI's most-wanted list and the subject of a manhunt before his September 2007 capture. He remained free for years by paying off military and police officials and forming a private militia of several hundred gunmen.