Later , at the grave of one of the murdered girls , Pendergast explains the rest of the mystery to Nora and Smithback . As a young man , Fairhaven became obsessed with his own mortality after witnessing his elder brother 's premature death from progeria . He used his real estate fortune to make generous donations to biomedical research , and came across mention of Leng in some of the Museum 's old records . Leng was still alive when Fairhaven tracked him down , though he was now an old man and had stopped using the formula ( Pendergast reveals that Leng abandoned his project in 1954 , after the Castle Bravo thermonuclear bomb was successfully test-detonated , deciding that mankind had already perfected a means of destroying itself ) . Leng was powerless against Fairhaven ’s feverish brutality , and died under torture by Fairhaven , but never revealed his secret formula - which Pendergast found in a hiding place in Leng 's laboratory
Castle Bravo
Castle Bravo
The Cabinet of Curiosities