Leuchter was also prepared to act as expert witness regarding crematoria ovens despite admitting during cross examination that he had no expert knowledge. Leuchter presented his own estimate of 156 corpses as the total daily incineration capacity of the installations at Auschwitz. During cross-examination, he was presented with a letter written by the Auschwitz Central Construction Office ("Auschwitz Zentralbauleitung") of June 28, 1943, from SS-"Sturmbannführer" Jahrling to SS-"Brigadeführer" Hans Kammler stating that the five crematoria installations had a collective daily capacity of 4,756 corpses. The capacity figures were for crematoria to be installed however never were. [https://www.hdot.org/day08/#] Leuchter conceded that this was quite different from his own figure, and that he had never seen the document in question before.