About 150 Thai and foreign customers were arrested at a club operating after hours off Sukhumvit Road in Bangkok's Watthana district in the early hours of yesterday morning.
The Insanity nightclub on Soi Sukhumvit 11 was raided about 3am by officials from the Department of Provincial Administration's law enforcement operations centre, aided by territorial defence volunteers.
About 150 people were inside at the time of the raid, most of whom were dancing to music.
"There was no social distancing to prevent the spread of Covid-19, and most of the people there were not wearing face masks," said Ronnarong Thipsiri, director of the DPA centre, who led the raid. "All tried to leave when officials arrived, and all were caught."
Some packets of white powder suspected by officials to be ketamine were found on the floor and in the toilets, Mr Ronnarong said.
According to a post on the centre's Facebook page, shisha tobacco and pipes were also found at the club.
Mr Ronnarong said all patrons found at the scene were tested for narcotics, and some tested positive for drugs -- although he stopped short of revealing further details.
The raid was carried out after officials received complaints from residents about the club staying open beyond permitted hours every night. According to police, the complainants were concerned the club may become a hotspot for coronavirus transmission.
Mr Ronnarong said his investigators found the club had no permit, sold alcoholic drinks after hours and stayed open until about 4am every night. Furthermore, he said, the club's management did not enforce disease control measures imposed in light of the Covid-19 pandemic.
The club's operator will face criminal action for violating an order issued by the National Council for Peace and Order, and the nightclub may be shut down for five years, Mr Ronnarong said.
The Metropolitan Police Bureau (MPB) has set up a panel to investigate how and why the club was allowed to operate beyond legal hours, as well as the origins of the drugs found at the scene, MPB deputy chief Piya Tawichai said.
When asked if local police responsible for the area would face transfers, Pol Maj Gen Piya said it will depend on whether they had demanded bribes or been negligent in their duties.
In a separate development, the Bangkok Metropolitan Administration is preparing to inspect boxing stadiums, pub, bars and entertainment venues in keeping with disease prevention measures, deputy governor Sopon Pisuttiwong said yesterday.
He said the venue operators will be asked to make sure their customers check in with the Thai Chana app so that they can be traced and contacted in case of emergencies.