In 1980 in St. Polten, Austria, Werner Kniesek broke into the home of 55 year old Gertrude Altreiter and her adult children, Walter and Ingrid. Over the course of several hours, Kniesek would torture the family before ultimately strangling them to death. The next day, he would take their car, loaded with the bodies of his victims, with him while he ran his personal "errands." He would eventually confess his crimes, and his motive, to the police after his capture.

Sources for this episode:
Astro Databank - Kniesek, Werner
Academic - Werner Kniesek
Wikipedia - Werner Kniesek
Wikipedia - Sankt Pölten
IMDB - Angst