Federal authorities have arrested four people in connection with a sophisticated drug smuggling operation that used a tunnel stretching approximately 2,000 feet between San Diego and Tijuana, Mexico, according to the Department of Justice.

The tunnel was discovered beneath a fake store called "Buy 4 Less" in San Diego following a monthslong investigation by Homeland Security. The underground passage featured reinforced walls, ventilation systems, and a rail system designed to facilitate the transport of illegal drugs across the border.

Authorities seized more than a ton of cocaine with an estimated street value of $45 million during the operation. The four suspects have been charged with drug trafficking in connection with the smuggling scheme.

The tunnel represents the latest discovery in ongoing efforts to combat cross-border drug trafficking between the United States and Mexico. Such underground passages have been used by criminal organizations to circumvent border security measures and transport narcotics into the United States.

The investigation that led to the tunnel's discovery was conducted over several months, though authorities have not released specific details about what initially triggered their interest in the location or the suspects involved in the operation.