 In 1912, he witnessed the well-known British mountaineer H. O. Jones, Jones's new wife Muriel Edwards, and their guide Julius Truffer fall to their death on the Aiguille Rouge de Peuterey.Preuss, who was unroped and scouting, returned only to watch Truffer fall due to a broken hold, taking the rest of the party with him.Preuss often climbed alone because he believed soloing to be safer; only his own life was at stake.