A 30-year-old man has filed a criminal complaint against actor Yoo Ah-in for sexually attacking him, Seoul police said Friday, with investigators considering the possibility that Yoo had been under the influence of drugs when it occurred.

Officials at the Seoul Yongsan Police Station are investigating the imitative rape case involving the 37-year-old actor, with plans to summon him for questioning soon. Imitative rape, stipulated by Article 297-2 of the Criminal Act, refers to rape via non-genital body parts.

Yoo's lawyer immediately released a statement Friday morning denying the allegations and urging the public to refrain from "unnecessary speculations" related to his client.

The accuser said he was sexually attacked by Yoo while sleeping at a unit of a commercial-residential building in Yongsan-gu, Seoul, on July 14. The unit is not the home of Yoo or the accuser and others were at the scene.

Officials said they are open to the possibility that Yoo had been under the influence of illegal drugs. They already questioned and did a rapid drug test on the accuser, and the results came back negative.

The embattled actor is currently on trial for repeated illegal drug use. He is accused of illegally using medical anesthetic propofol on 181 occasions between 2020 and 2022, smoking and instigating others to smoke marijuana, and instigating others to destroy criminal evidence.

Propofol is categorized as a psychotropic substance under South Korea's Narcotics Control Act and requires the prescription of a medical doctor for valid medical reasons.

The prosecution requested a four-year prison term for Yoo earlier this week in court.

Yoo has been touted as among the best acting talents of his generation, starring in several commercial hits and critically acclaimed films like the 2018 film "Burning."