On that evening, Hermann Schwarz, a 25-year-old local resident recently discharged from the army, opened fire at people in the street from the second-story window of his apartment.
In the initial shooting and the following siege Schwarz shot a total of twelve men, six of them fatally, before managing to escape into a nearby forest.
While police and townsmen engaged in an extensive search operation the gunman killed another person and evaded capture until the next day, when he was shot and wounded and subsequently taken into custody.
In the following months Schwarz was examined by several psychiatrists and was found to have a mental illness, resulting in his acquittal due to insanity.
In February 1912 Schwarz, his mother and two sisters moved into a small apartment in Romanshorn, where, at one point, he began stalking a girl.
A relative of that girl, an embroiderer named Wesel, reported his intrusive behaviour to the authorities, and asked for police protection when Schwarz threatened to kill him.
Because of that Schwarz was examined by his battalion's physician and was indeed found to be mentally unfit to fulfill his duties, so he was released from military service and sent home again on August 28.
Police were alerted about his behaviour and the Bezirksamt (District Office) ordered him to be confined and put under medical observation.
They encountered Schwarz in the hallway, but he resisted his arrest, threatened the officers with his revolver and, after a short scuffle, managed to escape into his room on the second floor and lock the door.
Anton Fritsch, a butcher's journeyman living in the same building, was called to assist the officers, but when he tried to break into the gunman's refuge, Schwarz fired through the door, hitting him in the chest four times.
He also injured a letter carrier named Hugelshofer, with a shot through the arm, apparently when firing at Etter, who was standing nearby.
Hermann then fatally wounded typesetter Rudolf Thommen with a shot through the lung, then killed inn keeper Friedrich Keller.
Fritsch was killed with four shots, 11 bullets recovered from Keller's body, apparently none of them fired from the gunman's rifle.