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.
The witness's testimony, combined with that of a handful of other witnesses, played a crucial role in the prosecution of Nazi camp personnel and high-ranking officials, as it helped to counterbalance the German efforts to conceal their atrocities at Chełmno by destroying evidence of the mass killings of Jews.