(Google Maps)
The tunnel discovered in late March connected a restaurant in Mexico with a residential home in Calexico, California, stretching more than 400 yards.
In late March, US federal officials shut down a smuggling tunnel stretching more than 400 yards from Mexicali, Mexico, to Calexico, California, arresting four people and seizing more than 1,500 pounds of marijuana.
The tunnel's entrance on the Mexican side of the border was under the floor in El Sarape restaurant, and the opening on the US side was found under a tile floor in the front room of a three-bedroom home at 902 E. Third Street, located about 300 yards from the border.
In the video below, posted by Baja California-based magazine Zeta, Mexican federal police are seen smashing through the tile floor of the restaurant in Mexicali, pulling out the plug used to seal the entrance, and inspecting the tunnel.
While tunnels have frequently been used by Mexican traffickers to move large quantities of drugs into the US (including marijuana seized from a stash house, the total haul from this tunnel was nearly 3,00o pounds of weed), the tunnel uncovered in Calexico was unique for several reasons.
According to US prosecutors, it was the first known instance of smugglers purchasing property on the US side of the border for the specific purpose of concealing a narco-tunnel entrance.
"The search warrant affidavit and charging documents allege the traffickers scouted properties in the area and selected the Third Street parcel in a residential section of Calexico," the US attorney for the Southern District of California said in a statement.
"The property sale was finalized in April of 2015 for $240,000 by the drug traffickers."
(US Immigration and Customs Enforcement)
The US entrance to a cross-border tunnel connecting Mexicali, Mexico, and Calexico, California, discovered in March 2016
This tunnel was also the second of three discovered over the last year in and around Calexico, an area that hadn't seen tunneling activity for nearly a decade.
In April 2015, men were observed around the All-American Canal, appearing to bring drugs into the US. When authorities responded, they caught a man in a wet suit and scuba gear, as well as $700,000 worth of meth. Further investigation revealed a partially submerged tunnel stretching from Mexicali to the US border.
(US Attorney's Office for the Southern District of California via AP)
This photo provided by the US attorney's office for the Southern District of California shows a plug that closed the entry point of of a tunnel at a restaurant in Mexicali, Mexico.