(Los Angeles Times) The powerful Sinaloa drug cartel is believed to be behind one of the most sophisticated and well-engineered smuggling tunnels ever found along the U.S.-Mexico border, according to U.S. drug enforcement officials who announced the discovery Thursday in Yuma.

The “fully operational” tunnel is a 755-foot passageway, tall enough for a 6-foot person to walk through, that burrows under the border fence, a park and a water canal. It connects a small, nondescript warehouse on the U.S. side to an inoperative ice manufacturing plant behind a strip club in Mexico.

It is outfitted with lights, fans and a ventilation system. The vertical shafts on both sides of the border descend 57 feet, creating what officials said were significant engineering challenges.

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