Eduardo Arellano Felix, one of a band of brothers who headed what was once Mexico's most powerful drug trafficking organization, was extradited to the U.S. on Friday, capping a 20-year effort to bring the siblings to justice in federal court.

Arellano Felix, 55, a onetime medical student nicknamed "El Doctor," was allegedly a key advisor in the Arellano Felix drug cartel, which during its heyday in the 1980s and '90s pumped tons of drugs into the U.S. and murdered hundreds while defending their turf in Baja California.

Arrested after a shootout in Tijuana in 2008, Arellano Felix exhausted all of his appeals in Mexico and was flown to San Diego on Friday afternoon. He is the last of the brothers named in the 2003 racketeering indictment to be extradited.

The investigation targeting the organization, also known as the Tijuana drug cartel, spanned decades and was spearheaded by a Drug Enforcement Administration-led task force in San Diego. Agents greeted the handcuffed, balding kingpin upon his arrival in San Diego.

"The extradition of Eduardo Arellano Felix today marks the end of a 20-year DEA investigation into this vicious drug cartel," said William R. Sherman, acting special agent in charge of the Drug Enforcement Administration's San Diego office.

Benjamin Arellano Felix, the leader of the organization, was sentenced to a 25-year prison term in April. Javier Arellano Felix, arrested on a fishing boat in 2006, received a life term. Another brother, Ramon, was killed in a shootout in Mazatlan in 2002.

The cartel, using Baja California as a staging ground to smuggle hundreds of tons of cocaine and marijuana into California, was known for its brutality and shrewd business dealings. Contacts in Colombia supplied the drugs while San Diego-area gang members served as paramilitary-style enforcers who eliminated rivals, law enforcement officers and informants.

Eduardo Arellano Felix was considered a major figure during the group's formation in the 1980s, according to investigators, but he assumed a lower profile after cartel gunmen were blamed for the 1993 killing of Guadalajara Archbishop Juan Jesus Posadas Ocampo.

Described by federal prosecutors as a senior advisor to Benjamin, Eduardo Arellano Felix allegedly ordered at least three killings in the 1990s. While hiding out in a middle-class Tijuana neighborhood in the mid-2000s, he allegedly served as an advisor to his nephew Fernando Sanchez Arellano, who was trying to maintain the cartel's power amid challenges from rivals.

The group's influence has waned significantly in recent years, and many experts believe Tijuana's trafficking corridor is now shared between the Sinaloa drug cartel and the remnants of the Arellano Felix group, led by Fernando Arellano Felix.

Eduardo Arellano Felix is scheduled to be arraigned Tuesday in San Diego federal court.