SEOUL, South Korea — A watchdog group says South Korea’s is hunting down and prosecuting gay servicemen after a video of two male having sex was posted on the internet earlier this year, stoking fear in an already persecuted minority group.

investigators looking into the case have threatened to out their gay peers, confiscated cellphones to check communication records, and even used dating apps to dupe into revealing their sexual identity, said Lim Tae-hoon, the head of the Human Rights Center for Korea, which tracks down abuses in the .

South Korea’s says it’s conducting a proper criminal investigation into allegedly involved with filming and uploading the video, which is a violation of the country’s communications laws and a penal code that makes homosexual activity punishable by up to two years in prison. The has denied allegations that investigators are using the case to embark on a broader mission to weed out gay .

investigators used the information they gained from the investigation on the sex video to track down other gay in the , starting by forcing the suspects to identify who they had sex with and then widening their search from there,” said Lim, who said a tipped his group off about the alleged crackdown.

In conservative South Korea, gays, lesbians, bisexual and transgender people are harshly stigmatized and struggle to be politically visible, while a powerful Christian lobby immobilizes politicians seeking to pass anti-discrimination laws. That stigma is amplified in the , where most able-bodied South Korean men are required to serve about two years as the country maintains a large force in the face of potential conflict with North Korea.

Gay men are not exempt from conscription but are banned from engaging in homosexual activity while serving, leading to an environment in which they serve without revealing their sexual identity for fear of discrimination and reprisals.

“South Korea’s doesn’t exclude gay men from compulsory duty, but once they enter the , they are seen as dangerous and treated as potential criminals, as the ongoing investigation shows,” said Han Ga-ram, an openly gay human rights lawyer.

He said the investigation had “touched off fear in the LGBT community.”

“Hate crimes against LGBT people are already a serious problem, and the government could make it worse by sending the wrong message by punishing gay men in the ,” Han said.

The doesn’t reveal information about how often it pursues cases against gay , but Lim said in the five years before 2017 he knows of only two cases where were prosecuted for homosexual activity. Since the start of the year, more than 30 have come under investigation and one has been arrested, an captain who did not know the involved, Lim said.

“The who are being investigated had sex with their partners under mutual consent and not inside the barracks,” Lim said. “The has infringed on the realms of privacy and is falsely claiming that these committed wrongdoings.”

Lim said the arrested captain had never met the who uploaded the video and he was arrested for allegedly obstructing the investigation by delaying his appearance for questioning due to his lawyer’s schedule. The captain’s lawyer could not be reached for comment.

Lim’s group in 2014 uncovered the bullying death of a 21-year-old conscript, a case that shocked the nation and led to calls for the Ministry to take serious steps to reduce bullying and hazing in the .

The didn’t provide details of its investigation into the video, including the number of being investigated or why the captain was arrested. It said in a statement that the investigation was proceeding legally and that the privacy of was being protected.

The also stressed that homosexual activity in the is banned to allow to maintain “sound and healthy private lives.”

“The will continue to deal with activities that disrupt the discipline of based on related laws,” the said in a statement.

South Korea’s stance runs counter to that of the United States, which maintains bases in the country and is its largest ally. In 2011, the U.S. repealed its policy, known as don’t ask, don’t tell, which banned open homosexuality in the . It now allows service members to reveal they are gay without fear of investigation or discharge.