He used aliases and ruses. His notebooks are filled with careful forensic analyses of ransom notes and other pieces of evidence. While you probably have never heard the name Wilmer Souder, he helped pinpoint criminals long before CSI was a thing. As Rich Press reports for the National Institute of Standards and Technology, Souder was a hidden pioneer of the field we now call forensics—and his work was a pivotal part of one of history’s most famous criminal cases.
Press tells the story of Souder, a man who underplayed his own role in history so much that he was nicknamed “Detective X” by one journalist. Originally an expert in studying dental fillings, Souder helped pioneer the field of forensic science while working at the National Bureau of Standards, the forerunner of NIST. The Bureau was founded in 1901 to set standard weights and measures for the United States, but its expertise in precise measurement was such that law enforcement soon turned to it for analyses they could not conduct themselves. NIST helps develop and validate forensic techniques to this day.
Recent archival research revealed that Souder worked on over 800 criminal cases between 1929 and 1954—and given Souder’s careful disguise of prominent cases to avoid leaks, many may have been prominent. The most famous that is known today happened in the early 1930s after the kidnapping and murder of iconic aviator Charles Lindbergh’s baby. The kidnapper left behind ransom notes which Souder photographed and analyzed. In 1935, he was one of multiple experts who concluded that the author was German—perhaps, as he wrote in one report, a former prison inmate who was used to cramping his writing to conserve paper. Souder he hid the fact that he was working on the case in his own notebooks, giving the case a different name and introducing its main investigator by an alias in the Bureau office.
Souder’s analysis helped point the finger at Richard Hauptmann, a German-born carpenter who had become a suspect after spending gold certificates used to pay the ransom. Long before OJ Simpson, Hauptmann’s 1935 trial was termed “the trial of the century.” Souder testified at the trial, and Hauptmann was convicted and executed by electric chair.
It’s not certain how many other pivotal cases Souder assisted in—but his role in helping develop the field of forensic science is clear. Souder used newfangled and increasingly complex tools like microscopes and optical instruments like interferometers to analyse handwriting, compare ballistics and identify forgeries.
In recent years, the validity of some forensic techniques such as hair analysis has come into question. But, says Press, Souder anticipated many of today’s questions, calling for more precise measurement methods and more stringent standards overall. Today, he is considered a forefather of the field—even though, thanks to his own low-key nature and the low profile he kept for the sake of his family's safety, he’s anything but a household name. Fittingly, the story of how his legacy has been tracked down by historians is a rousing detective tale in and of itself. Click here to check it out, or watch the video above for the whole, no-longer-secret scoop.