What is established is that he performed the procedure and charged $5,000 for it. The criminal market for fingerprint removal procedures existed; Loeser was one of the physicians serving it. Whether the practitioners who served this market believed their procedures would work, knew they would not but provided them anyway for the payment, or were simply uncertain is not documented clearly enough in available sources to resolve.
What can be inferred is that the underground medical economy serving criminals in the 1930s was not supervised by any professional or regulatory body. Practitioners who had lost their licenses, or who were operating in the criminal sphere because legitimate practice was unavailable to them, had financial incentives to provide services that clients demanded, regardless of whether those services would accomplish what clients hoped.
Loeser’s subsequent prosecution and incarceration for his role in the Dillinger case closed his criminal medical practice. His testimony about the procedures he had performed contributed to the documentation of the case.
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## The Director’s Investment: Hoover and the Dillinger Mythology
J. Edgar Hoover was the FBI director from 1924 until his death in 1972 — nearly five decades. The Dillinger case fell in the middle of the decade of FBI-building that most shaped the Bureau’s institutional character, and Hoover’s personal investment in the case’s outcome was substantial.
Hoover was not a field agent. He did not go to Chicago. He was not at the Biograph. But he was receiving detailed updates on the case’s progress throughout the spring and summer of 1934, he was personally briefed on significant developments, and his public statements about the case were carefully managed.