Actor Lee Sun-kyun of the Oscar-winning "Parasite" requested a lie detector test Tuesday for his ongoing drug investigation, claiming innocence, sources said.

Through his lawyer, Lee submitted a polygraph test request to the Incheon Metropolitan Police Agency in Incheon, about 30 kilometers west of Seoul, the legal sources said.

Lee has gone through three rounds of police questioning on suspicions of using marijuana and other illegal drugs at the home of a hostess working at a high-end bar in Seoul's Gangnam district on multiple occasions since early this year, including last Saturday.

The actor claimed he was tricked by the hostess into taking the drugs, and that he did not know what he was taking.

Lee tested negative in both the brief reagent test conducted during police investigations and the lab-based drug test by the National Forensic Service last month.

Lee's side insists that a lie detector test should be used in the investigation to determine the truth between Lee and the hostess, who has reportedly told the police that the actor used drugs at her home multiple times.

"If she was speaking the truth, the drug test by the National Forensic Service should have come back positive, but it was negative," Lee's lawyer told Yonhap News Agency.

"As Lee finds himself in an extremely unfair situation, a lie detector test should be conducted on both of them to scientifically verify who is speaking truthfully," the lawyer said.

The lawyer also expressed hopes on behalf of Lee that any further police questioning should be conducted behind closed doors, as the actor is feeling "burdened" by having his appearances before the police open to the public.

The police plan to soon decide whether to conduct a lie detector test after reviewing Lee's request. (Yonhap)