Police are tracking transactions between a Gangnam club called Burning Sun and police officers upon finding that the club, reportedly a hotbed of drugs and sexual violence, offered money to the police.

A regional investigation unit of the Seoul Metropolitan Police Agency is questioning former and incumbent officers of Gangnam Police Station over how they closed an underage clubbing case at Burning Sun last year, and booked a number of the ex-officers on bribery charges.

Gangnam Police Station closed an investigation into the club in August, citing lack of evidence, and sent the case to the prosecution recommending a non-indictment.

Among those booked is a former police officer surnamed Kang, who is suspected of acting as a link between the club and the police.

Police suspect that Burning Sun may have offered money to the police through Kang to avoid a suspension of business.

A club staff member who had been under police investigation for alleged possession and use of drugs was to be handed over to the prosecution Monday with a police recommendation for indictment.

Police are waiting for analysis results from the National Forensic Service regarding allegations that a Chinese woman known as “Anna,” who received commissions from the club for attracting customers, used and sold drugs.

The allegations surrounding Burning Sun began to receive media attention after Kim Sang-kyo, 28, claimed that he was assaulted by the police who arrived at the club upon his report that a woman was being sexually harassed on Nov. 24.

Two women, including Anna, had sued Kim for unwanted physical advances last year.

Burning Sun is owned by a group of people, including K-pop star Seungri of boy band Big Bang, who has spoken about his many successful business ventures on television.

Police have cracked down on Burning Sun amid suspicions of sexual violence against female customers after drugging them with GHB, a drug commonly used in date rape, in addition to a short sex video that was allegedly filmed at the club.

Police raided the club office and arrested a club employee earlier this month, and are focusing on uncovering the drug distribution channel.

Burning Sun closed Sunday after a year of business amid escalating suspicions.

By Kim So-hyun (sophie@heraldcorp.com)