Commandant of the Marine Corps Gen. Robert B. Neller came under scathing criticism Tuesday about the “Marines United” photo-sharing scandal from the Senate Armed Services Committee, especially from Senator Kirsten Gillibrand.

“If we can’t crack Facebook, how are we supposed to be able to confront Russian aggression and cyber-hacking throughout our military?” she asked Neller.

“This is a problem with our culture,” Neller responded. “I don’t have a good answer for you. I’m not going to sit here and duck around this thing. I’m not. I’m responsible. I’m the Commandant. I own this, and we’re going to have to change how we see ourselves and how we treat each other. That’s a lame answer, but ma’am, that’s the best I can tell you right now. We’ve got to change, and that’s on me.”

In what is being characterized as a “sad day for the U.S. Marine Corps and the entire Armed Forces” by congressional lawmakers on both sides of the aisle, Neller pledged to bring forth all of the military’s investigative resources for its pursuit of the Marines and former Marines who posted and shared the nude images and videos of female Marines and civilians.

Neller testified today in front of open and closed sessions of the Armed Services Committee, led by U.S. Navy veteran Sen. John McCain to discuss allegations surrounding nude photos shared in the secret “Marines United” Facebook group and other groups . Neller parsed his words carefully while answering senators’ questions to avoid unlawful command influence on the case, a military charge for when a person “bearing the mantle of command authority” exerts or appears to exert undue pressure on an ongoing military criminal investigation.

Neller decried the photo-sharing as detrimental to force-readiness and morale and asked more victims to come forward, saying none will receive any retribution from Marine Corps leadership. He did warn, however, that victims and whistleblowers do often face harassment and intimidation from anonymous crowds on the Internet. Neller added that while he has been “ignorant” on social media and cyber issues in the past, “I’m trainable.”

Gillibrand was not satisfied with Neller’s statements.

“We have countless victims who have come forward, and they’re not just being harassed online,” she said, her voice rising in intensity. “Once their name, face, where they’re stationed is posted, do you think the harassment ends online? It doesn’t. I spoke to a civilian yesterday who has continued to be harassed in her community because her ex-boyfriend exploited her online…so I have to say when you say to us, ‘It’s got to be different,’ that rings hollow.”

Sen. Ken Donnelly referred to The Daily Beast’s reporting in his statement about how Marines United has thumbed its nose at the Marine Corps.

“I went online and found already that there’s a Marines United 2.0, posting links to the same materials that already has over 3,000 members,” Donnelly said. “They are basically challenging you, General. They are thinking they can get away with this. You are the Commandant of the Marine Corps and I think it’s up to you.”

Sen. Lindsay Graham also asked about The Daily Beast’s coverage of the scandal when he demanded the name of an administrator of one of the later groups who taunted the Marine Corps about how after his honorable discharge from service, he was no longer subject to NCIS jurisdiction, nor that of the Uniform Code of Military Conduct.

“Who is that person?” Graham demanded. “Do we know their name? Let’s make them famous right here… We will publicly let the world know who this person is.”

The photo in question was previously reported by this journalist, but unpublished until now. The selfie was taken by Lance Cpl. Brandon D. Toftner and posted inside Marines United with the caption: “Hey NCIS, Suck my 3 inch flaccid cock.”

Toftner told The Daily Beast he was unaware that his comments in Marines United was brought up by congressional senators on Capitol Hill but defended his defiant statement via text message:

“It’s not illegal to say mean things to federal agents. That’s well within my First Amendment rights as an honorably discharged Marine. That is not breaking any laws,” he texted, adding: “Nothing, a dumb picture, yes. But zero laws were broken. I have the First Amendment to protect my free speech as a civilian.”

Neller said he agreed with Graham that the Marines United scandal is one of the darkest moments in the history of the Marine Corps.

“The irony is, we’re trying to increase the number of women in the Marine Corps,” Neller said.

Several senators asked questions about women’s place in the Marine Corps and whether the Marines United scandal is indicative of a deeper cultural problem.

“What more do women have to do to be accepted into the Marine Corps?” Neller asked in his opening statement, in which he mentioned five female Marines who recently died in combat zones. “We’ve got to earn [female Marines’] belief that they’re going to get the same opportunity as anybody else to compete and to be the best person they can be. We need to “earn the trust, of them, of this committee, and of the American people.”

He addressed male Marines at the end of his statement.

“To the men in our Corps, serving today, and those who no longer wear the uniform: You’re still Marines. I need you to ask yourselves, how much more do the females of our Corps have to do to be respected? …. What is it going to take to accept these Marines as Marines?”