A road in Dongdaemun-gu, Seoul.

A man and a woman are seen exchanging something on the street.

Similar scenes are captured on other days as well.

These are Chinese students receiving equipment, such as small earphones and transceivers to be used at the Test of Proficiency in Korean (TOPIK) exam sites, from members of a group organized for cheating and proxy testing.

The group, based in China, was found to have advertised cheating and proxy testing on Chinese social media, claiming that they could "guarantee a high score on the TOPIK."

They targeted the fact that TOPIK scores are widely used by foreigners for admission to domestic universities or graduate schools, employment at companies, and for obtaining permanent residency and stay visas.

It was determined that they charged approximately 2 million won for cheating using devices like transceivers and about 8 million won for proxy testing.

If a client wanted to cheat, the group had them listen to answers provided by an operative during the exam through an earphone. If they wanted a proxy test, the group recruited someone with a similar appearance and even created forged identification cards for them.

[Interview] Kim Seong-ho, Chief of the 1st International Crime Investigation Unit at the Seoul Metropolitan Police Agency: "They wear the cheating equipment on the back of their necks, and it reportedly blinks with a light. An exam proctor discovered this and caught them on the spot."

The police stated that the criminal proceeds earned over the four-year period from October 2021 to November of last year amounted to approximately 700 million won.

The police have apprehended one broker in Korea, one naturalized Korean who took proxy tests for 800,000 won per exam, and 11 Chinese nationals.

In addition, 101 Chinese nationals who requested the cheating or proxy tests have been booked on charges including obstruction of official business by deception.

The police believe that the ringleader based in China was responsible for producing identification cards, arranging proxy test-takers, and manufacturing and delivering the equipment, and they are currently tracking the individual through international investigative cooperation.

The police are also continuing their investigation into the identity of the operatives who provided the answers and the channels through which the answers were obtained.

Reported by Bae Seong-jae | Video by Kim Nam-seong | Video Editing by Yoon Tae-ho | Produced by SBS Digital News