Rudolf Diesel was a German inventor and mechanical engineer who is famous for having invented the Diesel engine, which burns Diesel fuel; both are named after him. He was born on March 18, 1858, in Paris, France, and died on September 29, 1913, at the age of 55 in the English Channel. The circumstances surrounding his death are mysterious and have been the subject of much speculation. Some researchers believe that he was murdered, potentially on the orders of the German Imperial government due to his refusal to grant the German armed forces exclusive use of his engines. Others believe that he committed suicide, motivated in part by financial troubles.

On September 29, 1913, Diesel disappeared from a steamer en route to London. His body was recovered on the shore days later. Before he left, Diesel gave his wife a suitcase of 20,000 Deutsch Marks in cash, and then boarded the steamship S.S. Dresden in Belgium. After he had dinner, he asked to be woken at 6 the next morning and went to bed. The bed in Diesel’s cabin hadn’t been slept in, although “his night attire was laid out on it,” according to the New York Times. Two further pieces of information point towards suicide being the more likely explanation. In a diary that Diesel had kept up to the day of his disappearance, he had marked September 29th with a cross, potentially indicating his intention to take his own life on that day. He also gave a bag to his wife before departing, instructing her not to open it until a week later. She found it contained over 200,000 marks, the equivalent of.

There was never an official investigation into Diesel’s disappearance, and the circumstances of his death remain a mystery.