The U.S. military campaign against self-proclaimed Islamic State may be focused on the male fighters conducting attacks across Iraq and Syria. But the richest human intelligence source to fall into U.S. hands to date is the widow of a senior ISIS member. She is revealing details about the terror group’s inner workings—including the existence of a parallel women’s network within ISIS that’s responsible for recruitment, retention, intelligence, and sexual slavery in the so-called caliphate.

U.S. military personnel captured Umm Sayyaf during a May raid targeting her husband, who was also ISIS’s chief financier who went by the nom de guerre Abu Sayyaf. After engaging in “hand to hand” combat with ISIS fighters, U.S. troops killed Abu Sayyaf and took his computers, cellphones, and documents that detailed how the group obtained and distributed as much as $2 million a day.

Umm Sayyaf is now the top female ISIS captive in U.S. custody, being held in Iraq and providing loads of intelligence beyond what American analysts found on the computers and cellphones seized during the raid that killed her husband, who ran ISIS’s oil and gas operations. Umm Sayyaf’s marriage to an ISIS higher-up gave her rare insights into how men run the financial and tactical operations. But she also played a commanding role in her own right, helping to run ISIS’s networks of women fighters and operatives, as well as playing enforcer for the men’s sex slaves, four defense officials told The Daily Beast.

“She was a principal adviser,” a senior defense official explained. “She has a lot of details."

There is a hierarchy within ISIS among women. A woman’s rank tracks with her husband’s. The higher in the ISIS org chart, the more she would know about the terror group’s operations. Umm Sayyaf is among an elite class of women within ISIS’s male-dominated hierarchy.

“Behind every successful man is a woman, and ISIS is no exception,” said a senior administration official who is closely following the interrogation of Umm Sayyaf.

But that doesn’t mean Sayyaf was part of the ISIS’s military chain of command, nor that she was helping design ISIS’s plan to take and hold territory, the official said.

“Was she influential? Yes. Did she have a commanding role? No,” the official said Thursday, speaking on condition of anonymity because he was not authorized to speak publicly. “She was not calling the shots on the direction of the ISIS enterprise,” though she was helping run the women’s network within ISIS, according to her and according to the documents retrieved by U.S. special operations from the site.

She’s not the first female to provide insights into ISIS. There have been several women who have publicly defected from ISIS. Some of them have told the U.S. how they were recruited, how they traveled from their home countries to join ISIS, and about the persistent campaign from men and women alike to commit to the cause. A few of these women have even explained how ISIS funded their travel and how they were able to dodge questions from concerned family about where they’d run off to.

But those accounts came almost exclusively from women lower in the ISIS hierarchy.

Sayyaf had a view from top to bottom, defense officials said. She has also provided details such as names of operatives and means of communication, two defense officials said.

“Umm Sayyaf is an anomaly,” said Mia Bloom, professor of communication at Georgia State University who studies the role of women in jihadi movements, in that Sayyaf served the traditional roles of a wife but also had visibility on ISIS’s command and control.

On the lower rungs of ISIS, women are tasked primarily with serving the sexual needs of ISIS’s male members, maintaining a home and producing future ISIS fighters, U.S. officials and counterterrorism experts said. In addition, in the territories that ISIS controls, there are women who work for the religious police, or Al-Khanssaa Brigade, ensuring other women are abiding by ISIS’s strict religious and social standards. Often they are Arab women who can tell others when they are not abiding by the rules. There are female spies there to make sure other women stay in line. And still others facilitate a sex slave trade, assessing other women or arranging temporary marriages for them.

U.S. forces detained Sayyaf, hoping she would have insights on ISIS treatment of hostages. Some suspected that she might know details about the kidnapping of American aid worker Kayla Mueller, who died while in ISIS’s custody.

What Sayyaf has said about Mueller and other hostages remains unclear. But U.S. defense officials said she has pulled back the curtain on ISIS’s operations, giving details about the organization and the men who run it in ways that could not have been understood through ISIS’s public statements or its aggressive Twitter propaganda campaign. And she is explaining ISIS’s dependency on women to keep and retain fighters and run the state.

Perhaps the person most like Sayyaf was ISIS leader Abu Bakr al Baghdadi’s ex-wife, who was reportedly detained by Lebanese officials late last year.

The interrogation of Sayyaf is also contributing the role women play in recruiting men to ISIS. Often it is the promise of a bride who will care for men as they fight in the frontlines that attracts fighters to the caliphate. (One recently arrested American ISIS recruit was told he could have “four wives,” according to the FBI.) Men who seek to live in strict jihadist interpretation of Islam also enjoy the promise of a wife whose life will mainly be at home.

Under ISIS, women’s primary role is to serve the needs of men, to keep the men fighting and residing in the caliphate. Upon arriving to ISIS, they are sent to a hostel, assessed by other women to determine their value, according to a report by the Institute for Strategic Dialogue, and then quickly married off, sometimes at ISIS’s marriage bureaus, in places like Raqqa, Syria, the group’s de facto capital.

“The roles women tend to have are primarily within the family—recruit, reward, and retain,” Bloom said.

But many women join ISIS in the hopes of becoming fighters themselves. That they don’t get a chance is a regression of sorts for women in jihadist movements, experts said. ISIS’s predecessor, al Qaeda in Iraq, deployed women as suicide bombers. Some terrorist offshoots like al Shabab, which is based in Somalia and is loyal to al Qaeda, and Nigeria’s Boko Haram, which has aligned with ISIS, also have used women as suicide bombers.

“We have yet to see [in ISIS] female commanders or suicide bombers,” said Bloom. “But because there is a precedent, they will always have that option.”

A defense official knowledgeable of U.S.-led coalition operations said he was not aware of any strike explicitly targeting women.

There are no official numbers of women with ISIS. But there are roughly 500 women on Twitter who claim to be residents of ISIS, and they are often the faces of ISIS’s propaganda war, telling other women they should join the caliphate. Experts assume that the ratio of men to women within ISIS is 10 to 1. With estimates of ISIS’s strength beginning at 20,000 fighters, that would mean at least 2,000 women are part of the self-proclaimed Caliphate.

Whatever the ratio, Umm Sayyaf has been so valuable that U.S. interrogators are learning more weeks into her questioning and have yet to decide what should happen to her next, two defense officials said. The interrogators have not yet determined if Abu Sayyaf is guilty of any crimes that are prosecutable in a U.S. court of law, in which case the U.S. would seek to extradite her from Iraq, the administration official said. If there’s not enough evidence to try her in the States, she may be handed to Iraqi custody. What happens to Umm Sayyaf then is unknown.

—with additional reporting by Kimberly Dozier