Some 500 men customers of the biggest room salon in Korea were questioned by prosecutors over charges of illegal sex trade earlier this month, officials said.

They were summoned by the Seoul Central District Prosecutors’ Office as part of an investigation into the bar named “Yesterday, Today, Tomorrow” or “YTT,” which hired more than 500 hostesses.

The owner of the salon, known only by his surname Kim, is suspected of bribing police officers, evading taxes and soliciting prostitution in his 19-story hotel in Gangnam, southern Seoul, where he also ran the bar from the first and third basement floors.

It is rare for the prosecution to summon hundreds of references for one case.

The customers, mostly in their 30s or 40s, however, rejected the summons, saying they were busy or away from home for work.

The prosecution persuaded them by saying that the summons was just for an inquiry without any intention of prosecution.

The men finally acquiesced to a call after they were asked over the phone if a summons could be sent to their home.

The room salon goers mostly used corporate cards, according to the prosecutors’ office, which could have been used by the bar owner to evade taxes.

The prosecutors raided YTT earlier this month to crack down on its illegal sex business and secure evidence of bribery to police officers and tax evasion.

Prosecutors were first informed about Kim and his illegal business operations while investigating another bribery case that involved another room salon owner, Lee Kyung-baek, and policemen.

Around 15 former and active police officers involved in the corruption case have been indicted.

Lee, who is widely known as a “Room Salon King,” was released from detention on July 17.

The appellate court gave Lee three years in prison with five years’ suspension of sentence, overturning a lower court’s verdict of three and a half years in prison. The court also charged him 550 million won ($480,000) with 300 hours of community service.

By Kim Young-won (wone0102@heraldcorp.com)