An increasing number of German jihadists have been drawn to the IS struggle in Iraq and Syria. The greatest fear for domestic security services is that they might carry out terrorist attacks on their return.
Wearing a stern expression, Germany's domestic intelligence chief, Hans-Georg Maassen, plays a somewhat blurry video clip for members of parliament and their research assistants.
The footage shows corpses on the dusty ground. A few men, fighters from the terrorist organization calling itself "Islamic State" (IS) stand above the pool of blood and mock the dead, laughing.
In a second clip, two young men beam into the camera. Each time he goes into battle, boasts one, he hopes to find someone "we can kill."
The men in the two videos are speaking German: 400 jihadists from Germany are already believed to have traveled to Syria and Iraq to join IS, Maassen explains, and the number is rising.
125 already in Germany
The Christian Democrats (CDU) and their Bavarian sister party have invited a number of experts to a special meeting about the security risks posed to Germany by the jihadists. All the assembled specialists are in agreement - that jihadists returning from Iraq and Syria pose a very real threat to Germany. At least 125 German jihadists have already returned to Germany, according to Maasen, who is president of Germany's domestic intelligence agency, the Federal Office for the Protection of the Constitution (BfV).
At least 125 jihadists have already returned to Germany, according to Maasen, 25 of whom were "demonstrably involved in combat operations."
Presumably, though, the number is higher. "In many cases, we simply don't know what these people are doing in Syria and Iraq," says Maassen. Not all jihadists use social networks to boast about what they have done. Many simply disappear from the radar and then eventually come back to Germany.
Maassen believes there is no simple solution, but says security services have done their utmost to prevent attacks
Attacks possible in Germany
It's a source of worry for the security services. They fear returnees may soon carry out attacks in Germany. Maassen shows the delegates a picture showing a black map of Germany dripping in red blood. It is a call for jihad against Germany, the intelligence boss explains.
"We are certainly also in the crosshairs of IS," Maassen adds.
But whether the leader of IS, the self-proclaimed Caliph who has given himself the name Abu Bakr al-Baghdadi, actually wants to attack Europe is something that has not been made clear, according to the Guido Steinberg from the German Institute for International and Security Affairs (SWP). Steinberg doubts that al-Baghdadi would, at present, divert resources from his struggle in Syria and Iraq.
Nevertheless, Steinberg assumes: "He will use the opportunities offered to him by fighters and structures in Europe."
And in Europe, Maassen claims there are a good number of people from within Salafist circles who support the goals and ideology of IS, who are at least sympathetic to them. Maasen claims that, as the "Islamic State" was proclaimed, there was "euphoria" among the approximately 6,200 Salafists in Germany.
The Caliphate that IS would like to build with violence in distant parts of the Middle East was, for many extremists, a realization of their dreams.
'Attacks could be carried out in Europe'
The more the West becomes involved in Syria and Iraq, the more the danger grows that returnees will come back with attack plans, Maassen believes. The US airstrikes against IS bases provide a motive for revenge attacks in the West.
Both Maassen and Steinberg stress that there is no simple solution. IS could generate considerable sums of money from oil production in the territories it occupies. In addition to that, says Maassen, it might make more money through taxes - as well as donations from IS supporters. Steinberg believes that only ground forces can drive IS from the major cities of Iraq and Syria. However, according to Steinberg, the current plans to train members of the Iraqi military to do this within their borders are insufficient. And for Syria, which would serve as a retreat for IS, there is no strategy at all on the part of the US or Europe.
Upwards of a hundred thousand Syrians have fled their homes amid tales of atrocities during the IS expansion
In addition, Turkey has prevented fighters from crossing the border to assist the Syrian branch of the Kurdistan Workers Party (PKK) in the fight against IS. The fear within the Turkish government is a strengthening of a Kurdish militia that launched an armed struggle against the Turkish state in the early 1980s. Germany, Steinberg says, should press Turkey to reach peace with the PKK.
As long as IS remains intact, more German jihadists might well join the fight. In a few cases, authorities have been able to stop potential jihadists from traveling. However, the radicalization of young people can take place very quickly - sometimes in a few months or even weeks. It often takes place in silence - in front of a computer at home. Not every young jihadist comes to the attention of their local mosque association - or the BfV.
The German security services have tried their best to keep Germany safe, claims Maasen: "We do everything that is within our power." Really though, it is impossible to fully guarantee security, he says. How could it be?
"We cannot watch the returnees around the clock," he adds.
While a home visit each week and the casual observation of suspects might be possible, the financial constraints alone rule out the viability of doing much more.