According to CNN, the famed Naval Criminal Investigative Service (NCIS) is looking into the online publication of hundreds of “explicit photos of current and former female Marines and other service members.”

A private Facebook group called “Marines United” contained a link to a Google Drive folder, where the photos were being stored, a US defense official told CNN. Members on the site solicited others to submit photos of women without their knowledge. The cloud storage folder has been removed at the request of the military, the official said. It was not clear to the Defense Department how many current and former Marines may be involved in potential wrongdoing. A former Marine originally brought the matter to the attention of the Marine Corps last month.

“We are thankful that Thomas Brennan, a Marine veteran, notified the Marine Corps and NCIS about what he witnessed on the ‘Marines United’ page. It allowed us to take immediate action to have the explicit photos taken down and to prepare to support potential victims. We are exploring what actions should be taken to best address this form of harassment in the future,” Marine Corps spokesman Capt. Ryan Alvis said in a statement.

Alvis said the Corps is “deeply concerned about allegations regarding the derogatory online comments and sharing of salacious photographs in a closed website.”

“This behavior destroys morale, erodes trust, and degrades the individual,” he added.

The Marine Corps Times reports the nude photo scandal has “shaken the entire Marine Corps.” Their report characterizes the offending Facebook page as “part of a perverse social media network that promotes sexual violence.” It is said to have almost 30,000 members, including both American and British Royal Marines. Participants were stationed across the world. Many of them unwisely used their personal Facebook accounts to join the Marines United group, making them easy for investigators to identify.

Although the Marine Corps Times was unable to contact the administrator of the Marines United Facebook page for comment, it quotes defenders of the group who said, “members have helped Marines suffering from post-traumatic stress, and that the group has reacted in force to help suicidal service members.”

According to this report, combat veteran Thomas Brennan of The War Horse website and his family have been subjected to threats since he exposed the salacious photos, including calls to assault, waterboard, and kill him.

Brennan told Marine Corps Times there was a “bounty on pictures of my daughter,” and “it has been suggested that my wife should be raped as a result of this.” Efforts have reportedly been made to post the addresses of Brennan’s family and friends online, to intimidate or target them.

The intimidation tactics don’t appear to be working. Visitors to The War Horse are greeted with both a link to Brennan’s bombshell report published at Reveal News and information on how to report “sexual harassment or misconduct on Marines United.” Before clicking the link, be advised some explicit language from the Marines United group is quoted in Brennan’s report.

Brennan described some of the photos he discovered as taken from “the consensual, but private, exchange of racy images, some clearly taken by the women themselves,” but others looked like the work of stalkers, taken without the women’s knowledge or consent. Some of the women identified in the photos said the images might have been stolen from their online accounts. One distinctly recalled being stalked by her surreptitious photographer.

A Marine Corps spokesman indicated that the Marine veteran who posted the Google Drive image link has been fired from his job as a subcontractor for the United States government. More attempts to post photos to the group were made in mid-February, even after the process of dismantling it was underway. Hearty encouragement to contribute more explicit photographs of women were made, including offers of free beer.

“There is no place for this type of demeaning or degrading behavior in our Corps. Let me be perfectly clear; no person should be treated this way. It is inconsistent with our Core Values, and it impedes our ability to perform our mission,” Sergeant Major Ronald L. Green told CBS News, which notes the scandal comes “just two months after the first female infantry Marines headed to Camp LeJeune.”