Seoul police said Tuesday that it is investigating a YouTuber suspected of livestreaming after taking sleep-inducing medication zolpidem, unprescribed use of which can be punished by South Korean law.

The woman in her 20s, whose identity was withheld by authorities, is believed to have taken the unprescribed drugs on Monday while broadcasting from a motel in Sinchon, western Seoul, according to Seoul Seodaemun Station.

Police raided the scene after one of her viewers reported that she seemed to be taking some kind of drug. Officials found several tablets of Stilnox, containing ingredient zolpidem tartrate, which was prescribed to another 20-something woman at the scene.

Taking zolpidem, which the Narcotics Control Act defines as psychotropic substances, like propofol, is legal only when prescribed by a medical doctor. Use or transaction of these drugs that has not been properly prescribed is punishable by up to five years in prison.

The two women are being investigated on charges of violating the Narcotics Control Act.

Drug-related crimes in South Korea have been on an upward trend. From January to September this year, 20,230 people were caught by police for drug-related crimes, a 47.6 percent increase from the same period the year before, according to the Supreme Prosecutors' Office.