The FBI internal memo documenting “unexplained differences” between the postmortem prints and the known Dillinger record is also a contemporaneous document. The memo attributed the differences to acid treatment. It declared a positive identification based on surviving ridge detail in the peripheral areas of the altered fingertips. This is the contemporaneous forensic finding.
Harold Cummins’s 1935 academic analysis confirmed the FBI finding’s scientific basis: acid damage concentrated in the central pattern areas, peripheral areas with sufficient surviving ridge detail for identification.
The 2019 comparison by Turbeville and Hallisey, using modern ACE-V methodology, found more than ten matching identifiers per finger in the available record — a finding consistent with positive identification under modern comparison standards.
The convergent weight of this evidence — contemporaneous forensic memo, early academic analysis, and modern independent re-examination — supports the conclusion that the postmortem prints were from John Dillinger, notwithstanding the alteration damage.
The autopsy discrepancies, the father’s reaction, and the alternative identity theory are not supported by documentary evidence of comparable strength. They are consistent with the simpler explanation: a chaotic night, a surgically altered body, and the imprecision of postmortem examination under difficult conditions.
The man killed at the Biograph Theater on July 22, 1934, was John Dillinger. The surviving ridges on his altered fingertips confirmed it.
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## The Fingerprint Division and the Scale of 1930s Identification
The identification of John Dillinger’s body was not an exceptional feat of forensic ingenuity. It was the routine application of a system that the FBI’s Identification Division had been building and operating for more than a decade.