Mexican authorities have arrested an alleged drug trafficker suspected of being involved in the abduction and killing of 20 tourists last September in the resort city of Acapulco.

Federal police said Tuesday they have detained Moises Montero Alvarez, whom they identified as a leader of the Independent Cartel of Acapulco. They said the 42-year-old was arrested along with another man and two teenagers.

Police accused Alvarez, nicknamed “the Korean,” of helping kidnap and kill 20 Mexican tourists from the state of Michoacan on September 30. Some of their decomposed bodies were later found in a mass grave and identified by their relatives.

Authorities say they think the drug traffickers might have mistaken tourists for members of La Familia, a rival drug cartel.