The attacker that recently blew himself up outside a music festival in Ansbach, seriously injuring 15 people, had no less than six Facebook accounts. He used at least one of them, registered under an assumed name, to distribute Islamist propaganda. And the 17-year-old Afghan that attacked travelers on a train near Würzburg with an axe a few days before also had two Facebook accounts.

The social media pages of criminals contain large reservoirs of information for police and prosecutors - they are therefore incalculably valuable in helping authorities find possible accomplices, understand motivations and rule out the threat of related future attacks. "Perpetrators often boast about their deeds online. They chronicle their preparations, their attacks, where they did what and where they hid their weapons," explains Saleh R. Iwas, an attorney for internet and data protection law.

Over the last three years, Facebook has received 300,000 information requests from investigative authorities, 16,000 of which were from Germany. The company regularly publishes these numbers in its annual transparency reports. The problem is: Facebook and Co., do not always cooperate. The German newspaper "Welt am Sonntag" (WamS) found that 37 percent of those German requests went unanswered.

Lack of good will?

André Schulz, chairman of the Association of Germany's Criminal Investigators (BDK) told the paper: "German police authorities submit requests several times a day but they are totally dependent upon Facebook's goodwill." He says that in most cases the BDK gets no reply, adding "it only goes quicker if we are dealing with suicide attacks, mass shootings, or terror threats."

The Ansbach attacker blew himself up and injured 15 people

German politicians from all parties agree that the situation has to change - and are therefore calling for a new law. "It has to ensure that these companies have foreign and domestic contact agents that can quickly process information requests," explains Bavarian Interior Minister Joachim Herrmann. North Rhine-Westphalian Justice Minister Thomas Kutschaty complains: "If it only takes ten seconds before a photo posted in Germany can be seen in New Delhi, then I expect Facebook to answer investigators' requests within an hour." The SPD politician went on to say that he failed to understand "why Facebook is being so resistant."

Is Facebook being intentionally uncooperative in order to hinder German investigations? The US company denies the accusation, saying that they have been fully supportive, and not just in connection to the attacks in Würzburg, Munich and Ansbach. However, the company also says that many of the requests in other cases were legally so flawed that Facebook could simply not process them.

In those other cases - murder, drug offenses, etc. - local and state police tend to be responsible for investigations, not the BKA. In fact, the BKA says that cooperation with the social network has been good: "Our experience has been that requests to Facebook are answered," a spokeswoman says. Yet she, too, speaks of formal mistakes.

Rainer Wendt: procedures are not always correct

Formal guidelines often not met

In an interview, the Federal Chairman of the German Police Union, Rainer Wendt, told DW: "A number of formal guidelines must be followed in international legal communication." For instance, a police agent must adhere to existing legal basis and use the correct terminology. "A lot of mistakes can be made," he admits. "Of course terror investigators at the BKA also have a completely different set of options at their disposal than local police." Nevertheless, Wendt does not see a problem in that. He says that it is often enough to investigate a perpetrator's social surroundings. If that does not lead anywhere, then officers occasionally return to Facebook. Yet, in most cases a look at a perpetrator's public profile is all they need.

"Facebook has grown too quickly over the last few years, and has too few employees. Therefore there is a prioritization about what needs to be handled first within the company. My experience has been that things that help business - like advising advertisers - have top priority." Police work and the like come much further down the line.

Wendt thinks calls for a new law are exaggerated. "German lawmakers tend to want to legally regulate the weather," he says jokingly. He has serious doubts about whether a German law could be passed that would in any way bind an international corporation like Facebook. "What will happen when Facebook ignores such a law? Nothing." Politicians are kidding themselves with such demands. Wendt says they would be better off improving police capacity; for instance, by hiring good investigators.