Name, education, references, and a preference of fighting over suicide operations are some of the 23 questions being asked of ISIS recruits, according to news reports.

German news organizations, including the Munich-based Süddeutsche Zeitung and NDR and WDR, the public broadcasters, said they obtained thousands of documents that include a list of 22,000 names of potential ISIS recruits.

NBC News and Britain’s Sky News also said they received similar lists, secreted to them on a USB drive by a former ISIS recruit named Abu Hamed who said he stole it from the head of ISIS’s internal security police.  

The documents, if authenticated, are likely to provide Western intelligence agencies the closest look at Western recruits to the terrorist organization, their motivations, their connection to others in the group, and ISIS’s sympathizers. News of the documents also comes a week after The New York Times reported that U.S. Special Operations forces had captured a “significant” ISIS operative in Iraq and were interrogating him at a temporary detention facility in the city of Erbil.

German authorities have looked at the list and, Süddeutsche Zeitung reported, called it “very likely to be real documents.” Thomas de Maiziére, the German interior minister, confirmed the authenticity of the documents, The Guardian reported, and said the list would help explain “the underlying structures of this terrorist organization.” All the documents have been turned over to authorities.

The BBC reported the documents seem to have come from late 2013 or early 2014. They look like initial recruitment forms, and show not only names of recruits, but ask 23 questions that cover things like who recommended them, if they have any previous combat experience, how they traveled out of their home countries, and their mother’s maiden name, as well as their blood type. Sky News also reported that many of the telephone numbers listed still worked, some of them belonging to family, but also “a significant number … used by the jihadis themselves.”

Some of the names on the list, like that of Abdel Bary, a young British rapper turned jihadist, shows up on the list. Bary is presumed alive, but authorities don’t know where he is. Others are fighters known already to be dead, or who are standing trial, like Kermin Marc B and Abdelkarim B, who are standing trial in Germany, the BBC reported.

Among the names on the list were at least 16 Britons, six Canadians, and four Americans. German authorities say that, in all, more than 800 of its citizens have left to fight for ISIS. Part of the difficulty of prosecuting these people though, is that once they return, it’s hard to prove they fought for the organization. The list will likely help with that.

An independent Syrian website called Zaman al-Wasl published copies of the questionnaires Tuesday. It also said it had exclusively received the personal information of 1,736 ISIS fighters.

These recruits came from 40 countries: A quarter were Saudi, and the list also included Tunisians, Moroccans, and Egyptians. When a potential recruit crosses into ISIS territory, Zaman al-Wasl reported, the border administration wants to know everything about that person, “even what he wants to be in ISIS, a fighter or a suicide bomber.”