A highly speculative thriller, The Hindenburg depicts a conspiracy leading to the destruction of the airship. In reality, while the Zeppelins were certainly used as a propaganda symbol by the Third Reich, and anti-Nazi forces might have had the motivation for sabotage, the theory of sabotage was investigated at the time, and no firm evidence for such sabotage was ever put forward. The possibility of Boerth's (i.e. Spehl's) deliberate sabotage is one theory of the fire that had been the subject of Mooney's book, published around the time of the film's development. It has never been proven definitively, and most airship experts tend to discredit this theory.