Prosecutors indicted three members of a voice phishing organization, suspected of manufacturing and supplying drug-laced beverages to students in a cram school district in Gangnam, Seoul.

The Seoul Central District Prosecutors' Office on Thursday indicted a suspect, identified by the surname Gil, under pretrial detention on charges of violating the narcotics law and for operating in a criminal organization.

Another suspect, surnamed Park, allegedly managed the group's voice phishing scams. A third suspect, also surnamed Park, has been indicted on a separate drug sales charge and faces an additional charge of supplying the drugs to Gil.

The three are suspected of colluding with a China-based voice phishing group to produce 100 bottles of the drink by mixing ten grams of methamphetamine with milk.

They then offered the drink to 13 minors, claiming that it was designed to help increase their concentration levels. Nine students consumed the drink, six of whom experienced hallucination and other related symptoms.

The group also attempted to blackmail the parents of six of the students, saying that they would report their children to authorities for drug use unless they provided hush money.

Prosecutors have applied the charge of forcing minors to use drugs for profit, which could result in the death penalty, life imprisonment or a prison term of at least ten years.