NOGALES, Ariz (CBS5/CNN) -- Federal authorities Monday night shut down the longest drug tunnel ever discovered in the southern Arizona border city of Nogales.
The 481-foot tunnel runs between two private homes in Nogales, AZ, and Nogales, Sonora, Mexico, U.S. Immigration and Customs Enforcement's Homeland Security Investigations said.
Three men were arrested and more than 640 pounds of marijuana and a half pound of heroin were seized during the takedown.
Jose Solorzano-Flores, 41, and Jose Mario Armenta-Valdez, 41, both of Mexico, and Jesus Alberto Ramirez-Valencia, 22, of Nogales, AZ, were charged with drug conspiracy in a federal complaint. The men made their initial appearance in U.S. District Court in Tucson Tuesday afternoon.
The tunnel stretches 411 feet from the U.S. entrance to the international border and extends for another 70 feet into Mexico, federal authorities said. The passageway is roughly two feet wide by three feet tall and contains wood shoring, electric lighting and fans to circulate air inside.
The tunnel was discovered after task force members developed information that drug smuggling activity was occurring at a private residence in Nogales, according to Homeland Security Investigations.
Task force members conducted surveillance on the house Monday night. They observed a vehicle, driven by Ramirez-Valencia, leave the residence, HSI said. After following the vehicle to a second house, task force members and Nogales police approached Ramirez-Valencia, who agreed to having the vehicle searched.
Inside the truck, authorities found 24 bales of marijuana weighing 590 pounds. They also encountered Solorzano-Flores outside the house.
Later that night, the HSI Special Response Team served a federal search warrant on the first house and discovered Armenta-Valdez inside.
Authorities then found the tunnel entrance on the lower level of the house. A half pound of heroin was found inside the house and two bundles of marijuana weighing 46 pounds were found inside the tunnel.
"This was one of the more complex and exhausting tunnels to investigate in recent Nogales tunnel history," said Kevin Hecht, deputy patrol agent in charge of Nogales Station Border Patrol.