SAN DIEGO -- A man identified by prosecutors as an operative for Mexico's Sinaloa drug cartel was charged with building two major cross-border drug tunnels, according to a federal indictment unsealed Wednesday.

Jose Sanchez Villalobos is accused of building, financing and overseeing the secret passages, which have proliferated along the U.S.-Mexico border in recent years as heightened enforcement on land has pushed smugglers underground. Previous prosecutions in connection with the tunnels have named low-ranking truckers and their supervisors who pick up loads of marijuana at warehouses in the United States after they already crossed the border.

Sanchez Villalobos, 49, was arrested by the Mexican army in January in the central state of Jalisco in connection with the seizure of $15.3 million two months earlier in Tijuana, Mexico. At the time, Mexico's defense secretary called him an operative for the Sinaloa cartel in Jalisco and Baja California states, which includes Tijuana.

The U.S. attorney's office in San Diego says he is alleged to be the highest-ranking member of a drug trafficking organization responsible for building cross-border tunnels, saying he supervised construction of the passages and oversaw movement of marijuana to the border. U.S. authorities have asked Mexico to extradite him.

The indictment, which was handed down in February, accuses Sanchez Villalobos of masterminding two of the most significant border tunnels ever found, both from Tijuana to San Diego.

On Thanksgiving Day of 2010, authorities found a roughly 700-yard passage equipped with rail tracks that extended from the kitchen of a Tijuana home to two San Diego warehouses, netting about 22 tons of marijuana on both sides of the border.

In November 2011, authorities found a 600-yard tunnel that resulted in seizures of 32 tons of marijuana on both sides of the border, with 26 tons found on the U.S. side accounting for one of the largest pot busts in U.S. history. The tunnel was equipped with electric rail cars, lighting and ventilation. Wooden planks lined the floor.

Sanchez Villalobos is charged with nine counts of conspiracy to distribute controlled substances, each carrying a minimum sentence of 10 years in prison and a maximum of life. He is also charged with several counts of building, financing or using tunnels, which carry maximum penalties of life in prison.

Federal investigators began tracking him in April 2010, while following leads on the tunnel discovered seven months later, said Lauren Mack, a spokeswoman for U.S. Immigration and Customs Enforcement. They concluded that Sanchez was storing large amounts of drugs in Tijuana.

The Tijuana-San Diego smuggling corridor was long controlled by the Arellano Felix family, which began to lose its grip in 2002 when its leader was arrested in Mexico and a brother was killed. In the last two years, the Sinaloa cartel – led by Joaquin "Chapo" Guzman – has gained an upper hand in the area.

More than 70 passages have been found on the border since October 2008, surpassing the number of discoveries in the previous six years.

The tunnels are concentrated along the border in California and Arizona. San Diego is popular because its clay-like soil is easy to dig. In Nogales, Ariz., smugglers tap into vast underground drainage canals.

San Diego's Otay Mesa area has the added draw of plenty of nondescript warehouses on both sides of the border to conceal trucks being loaded with drugs.

Earlier on HuffPost:

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  • In this photo released by U.S. Immigration and Customs Enforcement (ICE), a San Diego Tunnel Task Force agent lowers himself into the passageway of a cross-border tunnel that authorities say was used as an underground drug passage, Friday, Nov. 26, 2010, in San Diego. The tunnel found Thursday is 2,200 feet long, more than seven football fields, and runs from the kitchen of a home in Tijuana, Mexico, to two warehouses in San Diego's Otay Mesa industrial district, said Mike Unzueta, head of investigations at U.S. Immigration and Customs Enforcement in San Diego.

  • In this photo released by U.S. Immigration and Customs Enforcement (ICE), a San Diego Tunnel Task Force agent crouches inside a cross-border tunnel that authorities say was used as an underground drug passage, Friday, Nov. 26, 2010, in San Diego.

  • The tunnel found Nov. 26, 2010 is 2,200 feet long, more than seven football fields, and runs from the kitchen of a home in Tijuana, Mexico, to two warehouses in San Diego's Otay Mesa industrial district, said Mike Unzueta, head of investigations at U.S. Immigration and Customs Enforcement in San Diego.

  • This photo released by U.S. Immigration and Customs Enforcement (ICE) on Friday, Nov. 26, 2010, shows a close-up of the rail system in a cross-border tunnel that authorities say was used as a major underground drug passage.

  • In this Nov. 25, 2010 photo released by U.S. Immigration and Customs Enforcement (ICE), packages of seized marijuana are examined by officials in Murrieta, Calif., after a cross-border tunnel between Tijuana, Mexico and San Diego was discovered. U.S. authorities said Friday that they seized tons of marijuana in connection with a tunnel that was equipped with a rail car -- the second discovery of a major underground drug passage in San Diego this month. U.S. authorities followed a trailer from one of the warehouses to a Border Patrol checkpoint in Temecula, where they seized 27,600 pounds of marijuana, Mike Unzueta, head of investigations at U.S. Immigration and Customs Enforcement in San Diego, said.