He was attached to the Action T4 euthanasia program and worked at Hartheim, Hadamar, Brandenburg and Sonnenstein killing centers where physically and mentally disabled Germans were exterminated by gassing and lethal injection.

SS-Scharführer Erich Fuchs, who served with Bolender, testified about him in 1966: About thirty to forty women were gassed in one gas chamber.

In his own words: I assigned the Arbeitsjuden ("worker Jews") to different groups: some had to empty out the gas chamber after the cremation was completed; others had to transport the dead bodies to the graves.

[2] Also, according to Bauer, Bolender participated in gang rapes of female prisoners prior to killing them: I was blamed for being responsible for the death of the Jewish girls Ruth and Gisela, who lived in the so-called forester house.

[10] Moshe Bahir, a Sobibór survivor, wrote about Bolender:It is hard to forget Oberscharführer Kurt Bolender, with his athletic body and long hair, who used to go walking half naked, clad only in training breeches, carrying a long whip with which he brutally lashed the camp prisoners whom he came upon on his way.

More than once I saw him throwing babies, children, and the sick straight from the freight cars into the trolley with the load that went to the Lazarett [execution pits disguised as a field hospital].

[2]In December 1942, Bolender's duties at Sobibór were temporarily put on hold when he was sent to prison for intimidating a witness involved in his divorce.

[7][11] After World War II, Bolender assumed a fake identity, did not contact his family or his relatives, and after some time, had himself declared deceased.

It is probable that after the war he also went by the pseudonym Wilhelm Kurt Vahle while working as a bouncer at the Er- und Siebar and the Hofbräuhaus in Hamburg.

[4] At his residence police found a whip with the silver initials "KB", the inscription that was created at the camp by Sobibór survivor Stanisław Szmajzner.