A former Arizona Kentucky Fried Chicken restaurant was the end of the line for a drug tunnel between Mexico and the United States, federal officials said Wednesday.

Homeland Security Investigations and Yuma Border Patrol said the discovery was made after a traffic stop on Aug. 13, KTVK reported.

Special agents with Homeland Security said they found 118 kilograms of methamphetamine, 6 grams of cocaine, 3 kilograms of fentanyl, 13 kilograms of white heroin and 6 kilograms of brown heroin inside two toolboxes found in a trailer of a truck Ivan Lopez was driving, KYMA reported.

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Scott Brown, the special agent in charge of the investigation, said Lopez had been seen the same day taking the toolboxes from a building he owned that had been a KFC restaurant, KTVK reported.

Agents used a search warrant and found a tunnel in the kitchen of the former KFC, as well as Lopez’s home.

The tunnel from the restaurant was 8 inches in diameter, 22 feet deep and 590 feet long. It ended at a home in San Luis Rio Colorado, Sonora, Mexico, KTVK reported.

At that home, a trap door was found under a bed, and officials believe drugs were smuggled through the tunnel and pulled up at the end with a rope.

The fentanyl could be up to 3 million doses, KYMA reported.