He completed his degree and began doctoral studies, but in 1926 he abandoned this, instead working as a church publisher and later a journalist to support his family.
[1] Starting in December 1935, he wrote for Karl Ludwig Freiherr von und zu Guttenbergs journal Weiße Blätter [de] (White Papers).
While Klepper did not see combat, he served in a supply unit for forces through Bulgaria, Poland and Soviet Union before being discharged in 1942 to tend to his wife.
On 11 December 1942, after Adolf Eichmann refused visa for the couple's second daughter, the three of them committed suicide[1] by turning on a gas valve.
"[4] After their death, his sister Hildegard gave the diary to the Allied trial[clarification needed] against Adolf Eichmann where it was used as evidence against him (Session 51).