The attacker entered the supermarket and stabbed one person, who died at the scene, before fleeing the scene. While on the run, the suspect stabbed and injured four other people.
Officials wrote on Twitter that “the motive and the number of injured persons” were not yet known, but did confirm that “one person died.”
It was not immediately known if the assault had any connection to terror. ISIS has been urging its followers to use knives or vehicles in order to facilitate more attacks and Germany has been the site of past Islamist incidents.
But both German newspaper BILD and a witness to the assault said the man yelled “Allahu Akbar” during the bloody spree. The phrase, Arabic for “God is great,” is frequently shouted by Islamic extremists before an attack.
Police initially said they were looking for a second person in connection with the attack, however, later they said the man in custody was the lone suspect.
The supermarket was blocked off by police as they investigated the incident.