South Korean actor Lee Sun-kyun | PC: GETTY IMAGES

South Korean actor Lee Sun-kyun, best known for his role in the Oscar-winning film Parasite, has been found dead in an apparent suicide in central Seoul.

The Police say they had earlier received a report that he had left his home after writing a note and found the body of the actor in a car near a city park on Wednesday.

The 48-year-old had been under investigation for alleged illegal drug use since October.

According to reports, the body was taken to Seoul National University Hospital after police located his car near Waryong Park however, his family have refused an autopsy and he will be buried on Friday.

Police have begun an investigation to establish the details around his death, including when he arrived at the scene where his body was found, and the time of his death.

Yonhap news agency reported that he was suspected of taking drugs such as marijuana and ketamine with a hostess at a bar in Seoul. He had said that though he took what she gave him, he had not known that they were illicit drugs.

The hostess had reportedly told the police that he used drugs at her home multiple times – something he denied. He had earlier requested through his lawyer to take a lie detector test.

His drug tests had returned negative or inconclusive results, the report added.

Police said they regretted that Lee had died in the midst of investigations, but that the inquiry had been “conducted with [his] consent”, News1 Korea reported. Lee underwent three rounds of questioning, with one session last Saturday lasting 19 hours, according to Yonhap.

Lee’s agency, HODU&U Entertainment, said in a statement: “There is no way to contain the sorrow and despair. We respectfully ask that you refrain from spreading false facts based on speculation… so that [Lee’s] final journey will not be unfair.”

In Parasite, Lee played the patriarch of the wealthy Park family which is infiltrated by members of a poor family posing as unrelated individuals. The vicious social satire won four Oscars, including best picture.

The actor, who was married to actress Jeon Hye-jin and had two young sons with her, had a career spanning more than two decades.

He starred as the lead in dozens of films and TV shows, becoming a household name through the 2010s.

In South Korea, celebrities are held to high standards of propriety.

Lee had a squeaky-clean, family-man image prior to his alleged drug use, but reports that emerged from the investigation caused considerable damage to his reputation.

Speaking to reporters in late October before going into a police station for questioning, he said: “I sincerely apologise for causing great disappointment to many people by being involved in such an unpleasant incident.

“I feel sorry for my family, which is enduring such difficult pain at this moment.”

Lee was dropped from No Way Out, a mystery TV series that began shooting in October. According to reports, some businesses were seen taking down posters and advertisements featuring Lee from their stores.

Drug offences, including those involving usage of marijuana, are considered serious crimes in South Korea. Consumption of marijuana carries prison sentences of up to five years.