Three of the sites in the Tijuana area were identified by Santiago "El Pozolero" Meza, who has admitted using lye to dissolve bodies, SanDiegoRed.com reported Tuesday. A forensic team found organic material at one site.
"The search did not yield the results we were hoping for," said Fernando Ocegueda, who heads a group of families of suspected victims of drug violence.
Ocegueda said the three-day search began Dec. 19. The team included investigators from the agency in the federal attorney general's office dealing with organized crime, and officers from the Center for Missing or Lost People in Baja California.
The organic material was found in a water tank at a rural property. Bone fragments and other items were recovered at the site after Meza's arrest in 2009.
Meza told reporters after his arrest he had disposed of more than 300 bodies. He later said he had only dissolved 10 during a year at the farm.