For four months, the suspected kingpin of one of Mexico's oldest and most notorious drug cartels has been held here facing drug trafficking and other charges that carry up to 40 years in prison.

But now, Francisco Javier Arellano Felix could be eligible for the death penalty if convicted on fresh allegations outlined in a new seven count indictment claiming he and an underling ran a criminal enterprise and ordered the murder of Tijuana's deputy police chief and the beheadings of three police officers.

Arellano Felix, 37, and his subordinate, Manuel Arturo Villarreal Heredia, were expected in federal court Wednesday on charges of running a criminal enterprise, racketeering and conspiracy to commit racketeering, drug trafficking and money laundering. The killings were included as evidence of the criminal enterprise that authorities say extended into the United States.

That charge was not part of a 2003 indictment that led to Arellano Felix's arrest in August by the U.S. Coast Guard in international waters near La Paz, Mexico.

Officials at Mexico's Foreign Relations Department and attorney general's office said Tuesday they had no immediate response to the new allegations. David Bartick, an attorney for Arellano Felix, declined comment.

Eugene Iredale, an attorney for Villarreal, said his client would plead not guilty. He said any crimes alleged to have occurred in Mexico should be tried in Mexico, not the United States.

Laura Duffy, a federal prosecutor in San Diego, said the men can be tried in the United States because they directed operations on U.S. soil.

The new indictment alleges Arellano Felix ordered the murder of Hugo Gabriel Coronel Vargas, Tijuana's deputy police chief, who died Jan. 17, 2005, in a hail of more than 60 shots from an automatic rifle.

The indictment also charges that Arellano Felix and Villareal ordered the June 20 beheadings of three police officers from Rosarito Beach, a spring break spot just south of the border from San Diego.

Villarreal, 31, had not been charged with any crimes since his capture alongside Arellano Felix but also would be eligible for the death penalty if convicted of running a criminal enterprise. He was initially held as a material witness and has been in solitary confinement amid extradition proceedings to Mexico.

Arellano Felix is being held in San Diego without bail. He has pleaded not guilty to drug trafficking, money laundering and conspiracy charges from the earlier indictment.

The indictment alleges the men ordered the kidnapping, torture and murder of rivals in the United States as well as Mexico. It also says they smuggled cocaine and marijuana across the border in trucks and boats.

The Arellano Felix cartel emerged as a drug powerhouse in the 1980s in Tijuana, across the border from San Diego, but its influence has waned.