Singapore-
The "cheating operations" were "highly sophisticated", Deputy Public Prosecutor Vadivalagan Shanmuga said, Channel NewsAsia reports.
The students snuck in mobile phones and Bluetooth devices, and wore skin-coloured earphones during their exams.
Tan Jia Yan took the exams as a private candidate and FaceTimed questions to accomplices who then rang students and read answers to them, prosecutors say.
Poh Yuan Nie is alleged to have received from a Chinese national S$8,000 (£4,260; $6,100) as deposit and S$1,000 for every student referred to the Zeus Education Centre.
The plot was uncovered after an invigilator noticed unusual sounds coming from one of the students involved, prosecutors said.