This interpretation was developed in Law Enforcement Bulletin publications and in training materials for agents and local police departments. The Bureau was both a law enforcement agency and an institution engaged in building its own public reputation. The Dillinger case served both functions simultaneously.
Director Hoover was personally invested in the narrative the case provided. After the Little Bohemia disaster in April 1934, the Bureau’s credibility had been publicly challenged. The Biograph shooting and the subsequent positive fingerprint identification restored the narrative of FBI competence and scientific capability.
The specific fingerprint finding — that Dillinger’s acid treatment had failed, that the surviving peripheral ridges had allowed positive identification, and that the FBI’s identification infrastructure had worked exactly as designed even against a deliberate alteration attempt — was woven into the Bureau’s self-presentation throughout the late 1930s and 1940s.
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## The 1935 Academic Record: Cummins on Fingerprint Alteration
The most significant formal academic treatment of the Dillinger fingerprint case in the period immediately following the events was Harold Cummins’s 1935 analysis.
Cummins was a researcher in the field of dermatoglyphics — the scientific study of the ridge patterns of the fingers, palms, toes, and soles. He had been publishing in the field for over a decade by 1934 and would continue to do so for decades afterward. His analysis of the Dillinger case was grounded in both his expertise in fingerprint biology and his examination of the specific evidence from the postmortem identification.
His finding, as reported in subsequent accounts, was precise in its localization: the acid damage from Loeser’s procedure had been concentrated in the central pattern area of the fingertips. The peripheral regions — the outer areas of the finger surfaces extending away from the center — had sustained less damage and retained readable ridge detail.