The police failed to track down a sex buyer who transmitted HIV to a teenage student, local media reported Wednesday.
The 15-year-old victim, who met the man through a broker surnamed Joo, became infected with HIV after having sex with him in August 2016.
The victim and her family submitted a complaint against the broker in June.
While the family said the victim was forced into prostitution, Joo claimed the victim had agreed to work in the sex trade. Police sent the case to the prosecutor's office in September, accusing him of introducing 10 to 15 men to the victim.
Joo is suspected of receiving 150,000 won (S$180) to 200,000 won per man and sharing the money with her.
The police, however, reportedly terminated the investigation to track down the HIV positive sex buyer as a year has passed since the affair took place.
A source from police told Yonhap News Agency that the footage of security cameras and the chat history between the victim and the man have already expired, and the victim struggled to remember the exact place and time she engaged in prostitution with the man.