A group of men who were arrested for illegal drug possession and use on Thursday reportedly all had tested positive for AIDS, according to local media and police.

The drug investigation bureau under the Busan Metropolitan Police Agency said Friday they had arrested 61 male drug users, manufacturers and dealers who were infected with the disease for breaching the country’s Narcotics Control Act. Acquired immune deficiency syndrome is caused by the human immunodeficiency virus, which is frequently transmitted via sexual intercourse with an infected partner.

Of the total, 17 people, including a 30-something meth manufacturer who is presumed to be the main ringmaster, were taken into custody, while the other 44 were released without detention. Among those arrested are reportedly an official at Korail, the state-run railway operator, a social service worker and a lecturer at a private academy, according to reports.

The police investigation also found that the men had met through an application only available outside Korea, explaining they had confronted difficulties in tracking the men and their whereabouts. Police did not disclose the name of the mobile app the group had used to communicate.

Police say that the members administered the drugs at clubs and relaxation rooms that ensure privacy, and that drug purchases were made via the “drop off” method, where dealers would leave drugs at predetermined meeting places to skirt authorities’ radar.

The investigation also found that the main culprit had allegedly been producing meth using other drug-related substances at a motel in North Chungcheong Province from August 2021 through May 2022 and distributing it to drug users across the nation.