The sign on the barrels also threatened the life of "The Engineer" -- a nickname for Fernando Sánchez Arellano, head of the Arellano Felix cartel -- and "those who hang out with The Engineer," The San Diego Union-Tribune reported.

The barrels at Mariscos del Pacifico were discovered Tuesday. The same day, two bodies with their heads shrouded in tape were discovered several miles away near a water tower.

On Monday, a total of 16 bodies were discovered in Tijuana in two locations.

U.S. sources told the Union-Tribune that Mariscos del Pacifico, which specializes in seafood, belongs to Eduardo Gonzalez Tostado, who was kidnapped last year and freed by U.S. agents. The gang that carried out the kidnapping is said to target members of the Arellano Felix group, although Tostado denies any connections to drug gangs.