The fingerprint identification added a specifically scientific dimension to the story. The FBI was not just physically capable of running criminals to ground; it had the laboratory infrastructure to confirm identity through biological evidence. The identification of Dillinger’s body through his altered but still-readable fingerprints was used by the Bureau in public communications and in the Law Enforcement Bulletin as an example of both the durability of fingerprint evidence and the futility of attempting to defeat it.
The specific documentation of which ridges survived and which were damaged — including the memo noting “unexplained differences” attributable to acid and the confirmation of a positive match from surviving peripheral ridges — was incorporated into the Bureau’s expanding forensic science curriculum. The Dillinger case became standard material in training about fingerprint alteration and its limits.
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## Other Criminals, Same Futility
Dillinger was not the only gangster of his era who attempted to remove fingerprints, and the broader pattern of failures across multiple cases reinforced the Bureau’s message about the futility of the approach.
Alvin Karpis, one of the last major Public Enemy-era criminals to be captured, also had his fingerprints surgically altered. The procedure produced the same general result: surface damage that healed back toward the original pattern, leaving sufficient ridge detail for identification. Karpis was identified from fingerprints despite his alteration attempt.
“Handsome Jack” Klutas, an Illinois gangster, made a similar attempt with similar results. The acid treatments that circulated in criminal networks as a solution to the fingerprint problem were not, in practice, solutions. They were expensive, painful procedures that produced temporary and partial disruption of patterns that subsequently re-established themselves.