During the Operation Barbarossa, the invasion of the Soviet Union by Nazi Germany, he suffered severe injuries and lost an eye in September 1941.

His responsibilities included supervising male and female sorting squads in the Kanada warehouses and managing the administration of prisoner property and personal effects storage.

He developed a notorious reputation among the prisoners due to his unpredictable and violent behavior as an SS warden, earning him the nickname "William Tell of Auschwitz.

"[1][2] In June and July 1944, he fatally shot a prisoner in the head for failing to report for duty immediately after a short break.

In the sweltering afternoon heat, the people - men, women, and children - were led from the so-called new ramp along a pathway to the west, then north through section B II g towards crematoria IV and V. An unknown boy, approximately 6 to 10 years old, managed to move away from the other deportees.

In the camp, Weise and two other SS members were assigned to oversee the activities of approximately 25 female inmates in the clothing barracks.

[3] As the Eastern Front approached, it became evident to Weise and other SS members that the war was nearing its end, and the collapse of the Nazi regime was imminent.

Consequently, many SS forces stationed at concentration camps underwent a transformation in their treatment of prisoners, prompted by the growing fear of post-war accountability.

This change led to a reduction in arbitrary attacks and, in some cases, efforts to demonstrate benevolent behavior towards prisoners, particularly during the final stages of the war.

[3] During this period, it was common for SS members, including Weise, to seek out prisoners who could provide favorable testimony to absolve them of any wrongdoing.

Additionally, Weise occasionally engaged in deceptive conversations with prisoners, falsely portraying that his father was a Jehovah's Witness and claiming that his own involvement in the concentration camp was against his will.

During their march to Neustadt-Glewe, on May 3, 1945, the column encountered a motorcyclist on the highway near Hagenow, who informed them of ongoing artillery battles involving American forces nearby.

[3] Linda Breder, a Jewish prisoner working in the Kanada warehouses in Auschwitz, remembered Weise because of his cruelty and distinctive glass eye.

During the trial, Breder described how Weiss wanted to place cans, especially on the heads and shoulders of young boys, to use them as targets for shooting.

Breder also recounted how the women working in Kanada attempted to help a thirsty young boy who was on his way to the gas chamber by throwing water to him over the electric fence.

[1][4] Linda Breder's daughter, Dasha Grafil, described during the trial her confusion at how wealthy and influential Weise appeared to be, despite his horrific actions.

On the other hand, the testimonies of SS personnel were found to be incomplete: the witnesses either refused to speak or were very terse when questioned about the unpleasant aspects of the camp.

The trial records stated that "the witnesses' conscious or subconscious suppression of memories related to the subject matter was nearly complete and evident.

[6] On April 4, 1997, prompted by the then North Rhine-Westphalian Minister of the Interior, Franz-Josef Kniola, he was released from prison for health reasons.