THE PENTAGON -- The Defense Department is investigating online outlets through which Marines shared nude photographs of women, including fellow Marines -- some taken without their knowledge.

CBS News has learned the investigation has spread to all branches of the military.

The website titled Anon-IB first gained notoriety for publishing nude photos of celebrities like Jennifer Lawrence. But it also contains a message board for military personnel where men from all branches of the military exchange comments and nude photos of female service members, sometimes identifying them by name and/or duty station.Some of the pictures are pure porn, others are innocent snap shots followed by requests for wins, slang for nude photos.

“Anyone got any wins for this one?” someone asked about a young woman in the Massachusetts National Guard.This military-wide message board came to light just days after the exposure of a Facebook group called Marines United, which included nearly 30,000 active duty and retired Marines, some of whom shared nude photos of female Marines along with raunchy and sexually violent comments.

A criminal investigation has begun, and the top enlisted man in the Marines, Senior Master Sgt. Ronald Green, has told Congress that Marines United is just the “tip of the spear.”

James LaPorta, a former Marine turned journalist, said Marines United is spreading like a cancer to other chat groups.He sent CBS News one screen grab in which a member of Marines United asks “what are some other blue falcon free groups.” In Marine Corp slang, a blue falcon is someone who rats out his buddies.

Marine officials say they have received reports of at least a half dozen other sites.

Beyond the criminal investigation, Pentagon officials say sites like Marines United can do real harm to the military by discouraging young women from joining the armed forces and convincing those already in uniform to get out.