Officials said Sunday that the 39-year-old woman had previously attracted the attention of authorities after allegedly stabbing 18 people at the central railway station in Hamburg, Germany.
A state interior department spokesman said the woman is from northern Saxony and has been known to police since 2021.
“She appeared at the police station several times and showed obvious signs of mental illness,” the spokesman said.
The ministry said police filed several criminal lawsuits against the woman last year.
After the incident in early May, the court ordered her to be placed in a psychiatric hospital where she received three weeks of treatment.
The woman was released the day before Friday's attack, a spokesman said.
Authorities in Lower Saxony said there was no indication that the suspect might have used a knife in previous incidents and she did not have a gun permit.
A magistrate ordered the woman to be detained after being stabbed Friday.
