Teenager Safia S. described in chat conversations how she had travelled to Turkey and been in contact with “employees” of Isis, the Süddeutsche Zeitung and broadcasters NDR and WDR reported.
The chat logs further show that rather than travelling on to Syria from Turkey, Safia S. had had a “change of plans” when Isis members asked her to go back to Germany and cause a “surprise for the unbelievers,” police sources told journalists.
“They told me it would be of great use,” she reportedly said. Other passages show the girl talking about a “martyrdom operation”.
As it turned out, Safia's mother was the one to fetch her back from Turkey shortly before the knife attack in which she left a female federal police officer badly wounded in the throat.
There are “grounds for suspecting that behind the act was a a concrete instruction from ranking members of the so-called Islamic state,” a spokeswoman for federal prosecutors told the Süddeutsche Zeitung.
But Safia S.'s defence lawyer, Mutlu Günal, said that claims she had an “assignment from Syria” were “nonsense, that's not true”.
Paris attacks 'my favourite day'
Other conversations recorded in Safia's chat logs include one in which she described the November attacks in Paris, in which Isis terrorists killed 130 people with bombs and guns, as her “favourite day” - “because our lions were in action in Paris”.
The Hanover stabbing has left German security officials scrambling to investigate other possible attackers sent by Isis to carry out attacks in Germany.
Safia S. is currently under arrest on suspicion of attempted murder and supporting a foreign terrorist organization.
Those she chatted with are also under investigation for failing to report a crime.