Diesel boarded the post office steamer Dresden in Antwerpen to London. He took dinner on board the ship and then retired to his cabin leaving word to be called the next morning. He was never seen alive again. In the morning his cabin was empty and his bed had not been slept in. Ten days later the crew of the Dutch boat Coertsen came upon the corpse of a man floating in the North Sea near Norway. Personal belongings were identified by Diesel's son.