His testimony along with that of the few other witnesses was critical to the prosecution of camp personnel and other Nazi officials, because of the destruction of evidence by the Germans of their mass extermination of Jews in Chełmno.
His testimony, along with that of a few other witnesses, was pivotal to the prosecution of camp personnel and other Nazi officials, due to the Germans' deliberate destruction of evidence regarding their large-scale extermination of Jews in Chełmno.