The stepped-up efforts by authorities come as pop star Jung Joon-young was arrested Thursday on charges of filming and sharing a sex video without consent in a group chat on a social networking app. On Wednesday, police arrested two men accused of installing spy cameras in motels and filming illegal videos -- which filmed and live-streamed the private moments of more than 1,600 guests -- since last November.
The suspects allegedly set up cameras -- with lenses as small as 1 millimeter in diameter -- in 42 rooms at 30 locations in the provinces of Yeongnam and Chungcheong, which are about 85 miles from Seoul, police said.
Cameras were positioned inside power outlets, set-top boxes and hair dryer holders, police said. The videos were allegedly then transmitted to a website -- to which 4,099 people signed up, 97 of whom paid for videos, police said.
“This is an unprecedented case targeting unspecified masses at relatively small accommodations in rural parts of South Korea,” Jung Suk-hwa, chief superintendent at Korea Cyber Police, told ABC News.
Soo Jung Lee, forensic psychology professor at Seoul-based Kyonggi University, said spy camera crimes are increasing in South Korea because of the "cutting-edge internet and camera technology."
It "enabled users to create a unique online culture unlike that of any other countries," she told ABC News. "Sex crime regarding illegal filming is increasing every year, clearly growing faster than rape or indecent assault.”
There is a growing awareness of digital sex crimes, especially on secretly filmed sex videos, in South Korea. More than 6,000 sex crimes involving illegal filming were reported in 2017, according to South Korea's ministry of land, infrastructure and transport.
At a rally last summer, organized by mostly female activists, tens of thousands of protesters attended to denounce hidden camera pornography.
Laws targeting hidden camera crimes were strengthened last December, but many argue they're still too light. Those who illegally film sex videos are now subject to up to five years in prison and a fine of 30,000,000 Korean won, or just under $26,500. And those who intentionally spread secretly filmed sex videos face a sentence of up to seven years in prison, according to the country's national law information center.
Moreover, South Korea’s Supreme Court plans to modify sentence guidelines on hidden camera sex crimes in May to establish consistent sentencing practices.
“Penalties have become heavier for sex crime offenders, but the fundamental problem is that those who watch these illegally filmed sex videos are not punished,” Lee told ABC News. “Extension of women’s rights, as well as a change in social recognition that used to objectify women, is what we need to solve the problem.”
Jung's arrest brought the scandal worldwide notoriety. The K-pop celebrity had already been investigated for filming his girlfriend without permission in 2016.
Prosecutors ultimately acquitted him on those charges due to lack of evidence after Jung claimed his phone was broken.
Other idol band members, Choi Jong-hun of rock band F.T. Island and Seungri of 5-member group Big Bang, were alleged participants in the group chat where authorities say Jung shared sex videos. In a separate case, Seungri is being investigated for allegedly being linked to prostitution at a nightclub in Seoul.
The scandal exploded, in part, because those using new apps were still navigating the balance between privacy and breaking the law, Hern Sik Kim, a pop culture expert who teaches at an actors' academy, told ABC News.
“There was a lack of understanding of the nature of Social Networking Service, that everything is recorded within the internet space and that it can easily objectify or harm a third party,” he said.
There wasn’t much legal or social restrictions placed on Internet platforms in the past, Kim said. There were, for example, numerous video clips showing disturbing human rights.
That gray legal area allowed, experts said, for an underground market of sex tapes and pornography to emerge.
“K-pop stars accused of involvement in sexual crime is not limited to their own problem," Kim said. "This should be a social opportunity to change the recognition on sex crimes in South Korea as a whole.”
ABC News’ Hansol Park and Sorah Choi contributed to this report.