Mexican authorities say drug cartel assassins who killed three film students dissolved a total of twelve people in acid.

Interior Secretary Alfonso Navarrete said Thursday that investigators had found DNA from 12 separate people in residual fats found in tanks where one of the killers confessed to having dissolved bodies.

Navarrete did not say whether any of the DNA profiles matched those of the three film students abducted March 19 on the outskirts of the western city of Guadalajara.

The three were working on a film project for school at a house that was apparently being watched by members of the Jalisco New Generation cartel. One suspect said the cartel abducted the students, killed them and dissolved their bodies.

The house had once been used by a rival drug gang.