Hidden cameras secretly filmed hundreds of people in South Korean hotel rooms and live-streamed the footage.
A hidden spycam ring in South Korea allegedly secretly filmed about 1600 hotel room guests and live-streamed the footage online.
South Korean police have now arrested four men accused of using the hidden cameras installed in TVs, wall sockets and hairdryer holders.
The devices were found in 42 rooms at 30 hotels across 10 South Korean cities.
Police said there was no evidence the businesses knew about the breaches of privacy.
Producing and sharing pornography is illegal in South Korea, but the use of covert filming of sex and nudity has recently caused widespread public outrage.
Tens of thousands of South Korean women took to the streets in protests against the practices, under the slogan “My Life is Not Your Porn” last year.
Authorities reported more than 6,000 cases of illegal filming in 2017, up from 2400 in 2012.
In this most recent case, a site allowing members to pay for full videos or watch 30-second clips for free was created in November.
The site had more than 4000 members, including 97 who paid a US$44.95 monthly fee, according to CNN. South Korean police said the service brought in more than $8,000.
A spokesperson for the Seoul Metropolitan Police Agency told the Korea Herald police were targeting the practice of covert filming.
“The police agency strictly deals with criminals who post and share illegal videos as they severely harm human dignity,” the spokesperson said.
South Korean police said this was the first time authorities had caught suspects live-streaming such videos on the internet, according to CNN.
“There was a similar case in the past where illegal cameras were [secretly installed] and were consistently and secretly watched,” police said.
“But this is the first time the police caught where videos were broadcast live on the internet.”
According to the BBC, the men arrested posted 803 videos.
They face up to 10 years in prison and a fine of more than $37,000 if convicted.