Most members of the crew refused to believe that one of them would commit an act of sabotage, insisting only a passenger could have destroyed the airship. A suspect favored by Commander Rosendahl, Captain Pruss, and others among the "Hindenburg's" crew, was passenger Joseph Späh, a German acrobat who survived the fire. He brought with him a dog, a German shepherd named Ulla, as a surprise for his children. He reportedly made a number of unaccompanied visits to feed his dog, who was being kept in a freight room near the stern of the ship. Those who suspected Späh based their suspicions primarily on those trips into the ship's interior to feed his dog, that according to some of the stewards Späh had told anti-Nazi jokes during the flight, recollections by stewards that Späh had seemed agitated by the repeated delays in landing, and that he was an acrobat who could conceivably climb into the airship's rigging to plant a bomb.