Federal authorities have discovered another cross-border tunnel in rental house in downtown Nogales. 

Agents served a search warrant Tuesday at a house on West International Street and discovered the exit underneath a wooden front porch, said Kevin Kelly, assistant special agent in charge of U.S. Immigration and Customs Enforcement Homeland Security Investigations in Nogales.

U.S. Border Patrol agents and Mexican federal police crawled into the tunnel and tracked 70 feet into Mexico where it began in the underground drainage system that runs east to west below the city, Kelly said.

The tunnel was three feet wide by two feet tall with some shoring, he said. It went to a depth of four feet for about 19 feet long then sloped down to a depth of 20 feet before making a 90-degree turn. Finally, it went five feet south into the drainage system, Kelly said.

The tunnel was used to smuggle bundles of marijuana. Smugglers would lift up the wooden planks on the porch and load the drugs into a car, Kelly said.

The house where the tunnel was found is located on the street that runs along the U.S.-Mexico border, less than 2 miles west of the downtown Dennis DeConcini Port of Entry.

There have been no arrests made yet, but several are pending, Kelly said. He couldn't comment on whether the landlord is a suspect.

Nogales has become the tunnel capital of the U.S.-Mexico border in the last decade, with underground passageways found regularly in buildings, the street or other locations. This is the second tunnel discovered in a rental house in Nogales this year. In May, a 30-foot-long tunnel was discovered in a hillside rental house. Another was discovered in a rental house in Douglas in August.

Contact reporter Brady McCombs at 573-4213 or bmccombs@azstarnet.com