Bela Katz was the son of a prominent trader based in Sighet but had arrived at the camps before Eliezer’s group. The SS officers chose strong men to work at the crematorium and Bela Katz was one of them. He was recruited as a Sonder-Kommando and was even forced to place his own father’s body into the flames.
Eliezer and his father survived selection and were allowed to proceed to the barracks. Once in the barracks they were asked to strip naked as the SS officers took this moment to conduct their selection for the Kommandos. Eliezer thought it would be best to appear sturdy in order to be selected but his father thought otherwise. It was only when Bela Katz passed them a note telling them of his personal ordeal as a Kommando that both father and son understood the role this group played within the camps.
Because of his great strength, Bela Katz was forced to be a part of the Sonder-Kommando, the Jewish unit that worked in the crematories. One of his first jobs had been to put his own father's body into the crematory oven.
In Chapter 3, Elie and his father have just survived the selections upon arriving at Birkenau. For the present, they are alive, but as some SS officers move around their barracks looking for "strong men", they debate within their own minds the best means of ensuring their further survival. Elie wonders if, since the officers are so interested in strong individuals, it might be best to "pass oneself off as sturdy", but his father does not agree. Elie's father believes that above all, it is better not to draw atention to oneself.
Later on, Elie learns that his father's inclination was correct. Bela Katz, the son of a tradesman from Sighet, had arrived at the camp a week previously, on the first transport. His strength had been quickly noticed, and he had been forced into the most odious of jobs, carrying the dead into the crematories.