More than 1,500 hotel guests have been secretly filmed in South Korea, with the footage livestreamed to paying customers.
The practice was discovered in 42 rooms across 30 hotels around the country, police revealed on 20 March.
Cameras hidden in digital TV boxes, wall sockets and hairdryer holders streamed video to a specialist site that had more than 4,000 members, CNN reports.
Some 97 of those signed up paid $44.95 (£34) to gain access to additional features, including being able to replay particular scenes.
Two men have been arrested in connection with the scheme, while another two are being investigated.
There is no evidence that any of the hotels involved were complicit.
“There was a similar case in the past where illegal cameras were installed in (hotels) and were consistently and secretly watched, but this is the first time the police caught where videos were broadcast live on the internet,” police said.
Some 1,600 are thought to have been filmed, with the service making more than $6,000 (£4,546) since November 2018.
This is far from the first time secret filming has emerged as a problem in South Korea.
From May 2018, tens of thousands of women took to the streets of Seoul on a monthly basis to protest against secretly filmed pornography.
Many of the women covered their faces and some held placards that said: “South Korea the nation of spycam” and “My life is not your porn”.
Protesters urged the South Korean government to introduce laws to stop voyeurs using spy cameras to capture graphic images of women.
South Korean women and sometimes men have been plagued by hidden cameras that capture them undressing, going to the toilet or changing their clothes. The photographs and images are then posted on pornographic websites.
Reports of crimes with spy cameras have rocketed in recent years, from around 1,100 in 2010 to more than 6,000 in 2017.