(ATTN: CHANGES headline, lead; UPDATES throughout)
SEOUL, March 10 (Yonhap) -- Police on Sunday accelerated their probe into sex-for-favors allegations involving Seungri of South Korean boy band BIGBANG, as they booked him as a suspect and raided a Seoul nightclub associated with the performer to gather evidence.
Investigators are looking into the suspicion that Seungri used various nightclubs in Seoul's posh Gangnam district for lobbying and even attempted to introduce escorts to foreigners to encourage them to invest in his business ventures.
On Sunday morning, the Seoul Metropolitan Police Agency sent 20 investigators to raid the nightclub Arena to gather evidence about the swirling suspicions surrounding the 29-year-old singer.
"To secure a warrant for the raid aimed at addressing suspicions, we have booked Seungri as a suspect," a police officer said on condition of anonymity.
The police recently launched their preliminary probe into the case after local media disclosed social media messages last month that sparked allegations Seungri attempted to buy illicit sex services for potential foreign investors.
Police reportedly booked three or four others related to the allegations.
On Feb. 27, police questioned Seungri over the allegations. He also underwent a test over suspicion of drug use. He denies all allegations.
Last week, his agency, YG Entertainment, announced he will join the Army on March 25.
Separately, police raided the Seoul Regional Office of the National Tax Service last Friday as part of their probe into allegations of Arena's tax evasion.