Dr Karl Hoffmanstahl was a German surgeon renowned for his pioneering techniques. He performed experimental plastic surgery on René Heron for Professor James Moriarty. Because Hoffmanstahl knew about his plot, Moriarty decided to kill him. He therefore placed a bomb inside the payment box and sent Irene Adler to deliver it to him in a London auction house. Although Sherlock Holmes managed to intervene in time and defuse the bomb, Hoffmanstahl was killed with a poison dart by Colonel Sebastian Moran as he left the building.