Career
Nothing is known about his personal life. Stengelin served in the killing center at Grafeneck Castle in Grafeneck at Münsingen and the Hadamar Euthanasia Centre, before he was reassigned to the "Aktion Reinhard" extermination camp Treblinka. Then he came to Sobibor shortly before the uprising of the Sobibor extermination camp.
He was employed in the camp and was killed by the camp inmates during the uprising.
Franz Suchomel reported as the only witness of his death.