Fezer told reporters that the motive has not yet been determined, but “there are striking signs of a pathological psyche.”
She added that it is necessary to learn how to track down potential criminals who are psychologically unbalanced and driven by conspiracy theories.
Such attackers do not fit any threat profile, she said, warning that security services will need other indicators and action plans to deal with them.
Fezer spoke to reporters after answering questions before a closed-door parliamentary committee investigating the Dec. 20 attack that killed five people and injured more than 200.
The police in Magdeburg immediately arrested the 50-year-old Saudi psychiatrist Taleb al-Abdulmohsen, who has been living in Germany since 2006, at the scene of the attack.
Fezer said there were tens of thousands of tweets Abdulmohsen had sent over the years that had yet to be investigated.
“This explains why not everything is understood yet, there is a need to carefully look at who knew about what clues and what was passed on and when,” she said.
