Among one of the most prevalent theories for the destruction of the Hindenburg is the possibility of sabotage. According to historians, two men were primary suspects for both the FBI and German investigators: Eric Spehl, one of the airship's riggers, and Joseph Späh, an acrobat passenger. According to the theories, there was ample time for either man to plant an explosive and destroy the zeppelin. This possibility has been the focal point for a number of books and movies over the years.
The sabotage theory is based primarily on the possibility that someone detonated a flashbulb in the ship's rear section. This destroyed one of the hydrogen gas cells, causing a chain reaction that brought the Hindenburg to the ground. The only piece of evidence to support this possibility was found by the New York Police Department's Bomb Squad. While collecting forensic evidence, a solution that was likely to be derived from a battery cell was found amongst the wreckage. Investigators at the time postulated that a battery was used to power a flashbulb.
Much of the speculation surrounding Spehl was based on circumstantial evidence, mostly surrounding his political views. Investigated by the Gestapo, Spehl's girlfriend was known to have strong communist beliefs, causing a rift between the Nazi government of Germany at the time and himself. In addition, Spehl was one of the few with access to the section of the ship that was believed to be the origin of the explosion. Finally, the rigger also had a well-known interest in photography, making it possible for him to set up a flashbulb.
The problems with the possibility of Spehl being a saboteur stem largely from the fact that there is no documentation regarding the discovery of the battery solution near the location of the potential explosion. In addition, due to the fact that he died in the disaster, there was no chance to question him. Since the airship was 12 hours late, it is also questionable whether he would have been trying to destroy the Hindenburg on the ground or in the air.
The other suspected saboteur, Joseph Späh, did survive the fire, but was found to have no connection to the fire by the FBI. Again, much of the evidence pointing to Späh was purely coincidence. During the flight, he was seen telling anti-Nazi jokes to other passengers. In addition, he brought with him a German Shepherd which he had to feed during the voyage. This allowed him access to the stern, where he could have potentially planted a bomb. However, in order for him to have placed the flashbulb explosive where the spark is believed to have originated, Späh would have had to make use of his acrobatic skills and move up to a catwalk. While this is possible, no other evidence supports a motivation for sabotage.