Three men were arrested and a 481-foot drug tunnel in Nogales was shut down by federal authorities Monday night.

A multiagency investigation led to the discovery of the tunnel, which is the longest found in the border city, according to a U.S. Immigration and Customs Enforcement news release.

Authorities seized more than 640 pounds of marijuana and a half pound of heroin during the operation.

Taken into custody were Jesus Alberto Ramirez-Valencia, 22, of Nogales, Ariz., and Jose Solorzano-Flores and Jose Mario Armenta-Valdez, both 41, of Mexico, states the release. The men were charged with drug conspiracy charges and had their initial appearance in federal court in Tucson Tuesday.

According to the news release:

The tunnel runs between two houses in Nogales, Ariz., and Nogales, Sonora. The tunnel stretches 411 feet from the U.S. entrance to the international border and extends another 70 feet into Mexico.

The passageway is about 2 feet wide by 3 feet tall, and contains wood shoring, electric lighting and fans to circulate air.

"Through hard work, dedication and close cooperation, the Nogales Tunnel Task Force and our partner agencies shut this tunnel down in its early stages of operation, hitting the traffickers' bottom line before they could recoup their investment," said Eric Balliet, assistant special agent in charge of Homeland Security Investigations in Nogales.

Authorities found out that drug smuggling was occurring at a house in Nogales, Ariz. and while surveilling the house Monday night, they observed a truck driven by Ramirez-Valencia leave the house.

Task force members and Nogales police followed the truck to a second house and approached Ramirez-Valencia, who consented 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.

A search warrant was served on the first house and authorities found Armenta-Valdez in the house. They also found the tunnel entrance on the lower level of the house and a half pound of heroin. Two bundles of marijuana totaling 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 the Nogales Station Border Patrol. He said the investigation was completed with the cooperation of U.S. federal and Mexican authorities.