Mexican man linked to drug tunnels pleads guilty

A Mexican man linked to two of the largest marijuana seizures in U.S. history pleaded guilty to drug charges Tuesday in federal court.

Prosecutors allege Daniel Navarro oversaw the transport of 49 tons of marijuana through two sophisticated cross-border underground tunnels into California.

The tunnels and drug loads were discovered Nov. 2 and Nov. 25.

Navarro pleaded guilty to conspiracy to distribute more than 1,000 kilograms of marijuana. He faces 10 years to life in prison when he is sentenced Aug. 19.

U.S. investigators suspect both tunnels were overseen by Mexico's Sinaloa cartel, whose leader, Joaquin "El Chapo" Guzman, is that country's most-wanted drug lord. They were lined with rail tracks, ventilation and lighting.

A truck driver, Carlos Cunningham, 28, was sentenced in April to nearly 22 years in prison for hauling about 10 tons of marijuana through one of the tunnels. Another driver, Jose Guadalupe Hernandez, pleaded guilty in April for conspiring to distribute nearly 14 tons of marijuana in connection with the second tunnel discovered in November. He is scheduled to be sentenced in June.

U.S. officials have found more than 125 underground tunnels along the border built by Mexican drug cartels to elude detection since the early 1990s. Of those, 75 have been found in the past four years. Many were discovered before they were completed. The majority were found along the California and Arizona borders with Mexico.