Complex sentence: Furthermore, the existence of a journalist named Norbert Lenz has also been questioned, as there is no proof that he ever existed in the first place, nor has any employee at the German Hygiene Museum ever recalled the project ever existing, when asked.
Split into simpler sentences: Furthermore, the existence of a journalist named Norbert Lenz has also been questioned, as there is no proof that he ever existed in the first place. Finally, no employee at the German Hygiene Museum ever recalled the project ever existing, when asked.