Though less famous (or notorious) than some of his peers, John Fitzgerald Byers called him probably "the most evil" Nazi to be offered asylum. During World War II, he experimented on Jewish concentration camp inmates, his particular interest being the effects of water or extremes of pressure on the human body. To this end, his many "subjects" were drowned, suffocated, and placed in decompression chambers. After Klemper informed the Well-Manicured Man that he had seen Mulder, the Syndicate had him killed, faking a death from heart failure. (TXF: "Paper Clip")