SEOUL - The South Korean man behind a Telegram sex crime ring was paraded in public on Wednesday (March 25), in a rare move by the police to expose his identity after news of his alleged acts triggered public outrage.

Cho Ju-bin, 24, was arrested last week for sexually abusing 74 women, including 16 who are underage, in order to run a series of sex chat rooms on the instant messaging app. It earned him hundreds of millions of won in cryptocurrency from a subscriber list of up to 260,000 people.

In what is described as "virtual slavery", he allegedly lured and blackmailed the women into sending obscenely brutal images and videos of themselves, then posted them in chat rooms that charged participants as much as 1.5 million won (S$1,760) for viewing.

Police said Cho faces charges including coercion, sexual abuse, and violation of the Child Protection Act.

"Thank you for ending my unstoppable life as a devil," he said on Wednesday outside Jongno Police Station in central Seoul.

"I apologise to those who were hurt because of me," he added, avoiding the mention of his victims.

His apology failed to appease angry members of the public gathered outside the police station who saw his response as lacking in remorse.

Some people shouted at him to suffer for his wrongdoings, while others urged the authorities to hand him the stiffest punishment for his crimes.

More than five million people have signed at least three petitions filed on the official website of the presidential Blue House, calling for Cho and the subscribers of his so-called "Nth room" chat groups to be named and shamed in public.

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In response, President Moon Jae-in has pledged to take stern action against cyber sex criminals such as Cho.

An official later said the President also wants to change the misperception that criminals who hide in anonymity will not be caught.

However, observers said that punishment against such offenders is too lenient, and there are no specific laws targeting digital sex crimes.

Highly-wired South Korea has become a hotbed for Internet sex crimes, with a growing number of pornographic websites, including the infamous revenge porn site Soranet, busted in recent years.

Official data shows that the number of sex crimes using spy cameras have surged from 412 in 2013 to 2,388 in 2018.

The Korea Herald newspaper, in an editorial, called for stiffer penalties for sexual exploitation of children.

It noted that those found guilty of possessing child pornography can get jailed for up to a year or fined up to 20 million won. "This is a slap on the wrist compared the the US" where offenders can get a maximum of 20 years' jail, the English-language daily added.

Forensic psychology professor Lee Soo-jung of Kyonggi University stressed the need for South Korea to pass laws against cyber sex crime.

"We cannot strictly punish the offenders now because we have no such laws," she said in an interview with cable channel JTBC.

On Wednesday, a parliamentary committee adopted a resolution urging the need to strengthen punishment against online sex crimes such as the Nth room case.

The resolution noted that such crimes are of grave concern as they destroy societal ethics and morals and "destroy people's souls", according to Yonhap news agency.

Investigations are still ongoing. The police have so far arrested 126 people in relation to the case, including Cho, who was handed over to the prosecution on Wednesday.

To appease public fury, the prosecution has set up a 21-member task force to investigate Cho's case, including experts in youth crimes.

The police also launched a special unit on Wednesday to focus on digital sex crimes and strengthen cooperation with overseas law enforcement agencies to track down offenders.