A photo of Kim Na-jung posted on her Instagram page (Instagram)

A South Korean model who confessed to using drugs in the Philippines is under criminal investigation, according to police on Friday, after a rapid drug test came back positive.

Kim Na-jung, 32, is currently under investigation for illegal drug use by the Gyeonggi Bukbu Provincial Police Agency. She is to face questioning as to how she obtained the drugs and from whom, including possible accomplices, without physically detention. She tested positive in a drug test she took at Incheon Airport shortly after she returned from Philippines' capital Manila on Tuesday.

Kim, a TV announcer-turned-model, made headlines after she confessed to drug use on Instagram early Tuesday. She claimed to be in a life-threatening situation and unable to get on her flight slated for Monday evening. She believed everyone at the airport was spying on her.

It was revealed that Kim reached out to the South Korean Embassy in the Philippines for help leaving the country, during which she also confessed to drug use. She was able to get on a plane later in the day.

Kim's mother, who was in Seoul on Tuesday, reported to police that her daughter appears to have been kidnapped.

The nature of the danger Kim claimed to have been facing in Manila is unclear as of now.