South Korean police on Tuesday raided the Incheon police agency over allegations of leaks related to the drug investigation into actor Lee Sun-kyun, whose death in December sparked criticism of how the case was handled.

A media outlet that revealed detailed information about the Lee case also being investigated, reports said, with the focus on whether the police had given them the information.

Investigators from the Gyeonggi Nambu Provincial Police Agency on Monday procured evidence from the Incheon Metropolitan Police Agency, including mobile phones of some of the officers involved in the drug crime investigation unit and records of the investigation.

Officials declined to comment on the specifics of the ongoing probe, but stressed that it would be "swift and strict."

Lee, under investigation since October on suspicion of drug use, was found dead in his car on Dec. 27 in an apparent suicide.

The late star had been summoned three times by the police in the two months leading up to his death. His police visits were highly publicized in spite of Lee's request for them to be kept private, raising suspicions that the dates on which he was questioned had been leaked.

In light of the dispute, Oscar-winning director Bong Joon-ho of "Parasite" and other prominent figures in South Korean entertainment released a joint statement on Jan. 12 criticizing the police and media.

They submitted a joint petition three days later to the National Police Agency, the National Assembly, and KBS, who in November revealed a recording of a private conversation involving Lee that had been the subject of nationwide controversy.

The group demanded a thorough probe into the investigation of Lee, legislation to protect artists' human rights, and demanded KBS delete the articles that are "unrelated to the purpose of the media."

Police said last week that it had begun an investigation into how the Lee case was handled, with the anti-corruption and financial crime unit of the Gyeonggi Nambu police being tasked with finding out if and how the information was leaked to the public.

Allegations of blackmail against a 29-year-old hostess of a bar in Gangnam and a 28-year-old former actress -- who is believed to have coerced money from Lee -- is also being conducted by police. The hostess is currently under trial for extortion, and the former actress has been indicted Tuesday on the same charge by the Incheon District Prosecutors' Office.

Lee, who was 48-years-old, became famous through his roles in TV dramas such as "My Mister" and "Coffee Prince," and later for his role in the Oscar and Cannes award-winning film "Parasite."

He maintained until his death that he had been tricked by the aforementioned hostess into taking the drugs, requesting a polygraph test to determine whether he or she was telling the truth.

He had tested negative in both the reagent test conducted during a police investigation and a comprehensive lab-based drug analysis of his hair samples by the National Forensic Service.