The alleged poison attack at the Technical University (TU) Darmstadt is said to have been carried out by a 32-year-old student from Mainz.
According to the prosecutor's office and the police on Thursday, the woman was arrested and admitted to a psychiatric hospital on Wednesday.
The investigators assume that the 32-year-old poisoned drinks in a TU building in August last year.
Seven people were injured as a result.
According to the information, the suspect has been enrolled as a student of materials science since the winter semester of 2017.
The public prosecutor accuses her of attempted murder while incapacitated.
The woman has not yet commented on this.
According to investigators, she appeared suspicious early on.
But it was only after more than 1,000 witnesses were questioned that the suspicion was confirmed.
The public prosecutor suspects that the motive for the attack was that the woman felt persecuted by employees of the TU.
In the case, the police had set up their own murder commission (“Light”).