After the end of the war and a failed attempt to complete his baker's journeyman apprenticeship, Boost became a casual worker and escape aid in the later East Germany.
In 1949, Boost married and moved the following year with his family, consisting of his wife and two daughters, to his mother's home in Düsseldorf, West Germany.
While Servé was shot in the head and killed, Hüllencremer feigned death, at the whispered suggestion of Boost's accomplice.
In November 1955, the police uncovered a sunken car from a gravel pit near Düsseldorf-Kalkum, where the bodies of 26-year-old Friedhelm Behre and his girlfriend Thea Kürmann were discovered - both robbed and killed, akin to the attack on Servé and Hüllencremer.
The next day, in a haystack not far from the vehicle, the bodies of the missing 20-year-old secretary Hildegard Wassing and her date Peter Falkenberg were found.
He confessed to the attack on Bernd Servé and his partner in 1953, stating that Boost had killed his victim by a targeted headshot.