Some photographs show female Marines posing topless in their dress uniform slacks, or with their camouflage blouses open, in pictures they thought would forever be secret. Others show private moments swiped from their personal social media sites.

In one photograph, surreptitiously taken in February, a female corporal from Camp Lejeune, in North Carolina, is shown bent over from behind. The image, once posted online, was flooded with derogatory comments, including suggestions that she should be raped.

Now the Defense Department has opened a criminal investigation and the Marine Corps is facing its latest unwanted controversy after it was revealed over the weekend that a secret online Facebook group of active-duty and veteran Marines shared thousands of naked and private photos of Marine Corps women.

The invitation-only group, called Marines United and made up of more than 30,000 active duty Marines and veterans, built online dossiers on Marine women without their knowledge or consent, listing dozens of women’s names, ranks, social media handles and where they are stationed.