Germany's Interior Minister Thomas de Maiziere on Tuesday said that a trove of confidential "Islamic State" files will facilitate "speedier, clearer investigations and stricter prison sentences" for returnees.
The documents contain personal information about foreign fighters, including those from Germany, who joined the militant group in Iraq and Syria.
The material is based on "entrance interviews" aimed at determining the incoming fighter's status in the "Islamic State," according to a report by Munich-based newspaper "Süddeutsche Zeitung," which broke the story on Monday with public broadcasters WDR and NDR.
The report stated that those who freely volunteer themselves to join the "Islamic State" had to answer 23 questions that included information on their residence, religion, family status, education and so-called "jihadist experience."
The German attorney general knew of the files, and was working with authorities to identify citizens returning to the country after fighting alongside the "Islamic State," the "Süddeutsche Zeitung" reported.
"It helps us to understand the underlying structures of this terrorist organization," the interior minister added.
Following the report, a Federal Criminal Police Agency (BKA) spokesperson confirmed that the agency was in possession of the cache of documents, adding that experts determined their authenticity. However, the spokesperson did not specify how the agency obtained them.
According to domestic intelligence agencies, more than 600 German citizens have joined the militant group in Iraq and Syria.
The announcement comes as European and American counterterrorism apparatuses bolster efforts to curb homegrown terrorism inspired by the militant group.
In January, Europol - the EU's law enforcement agency - announced the formation of a strategic center to combat terrorism in Europe, tasked with boosting intelligence-sharing among member states and tracking militants' finances.
ls/rc (dpa, Reuters)