After the successful conclusion at the Biograph, Hoover used the case extensively in his public communications about the Bureau. The death mask sent to his office was part of a physical collection of case artifacts that served as tangible evidence of the Bureau’s effectiveness. The fingerprint identification, specifically, was used in public communications as evidence of the Bureau’s scientific capability.
The relationship between Hoover and Melvin Purvis — the Chicago SAC whose name became publicly associated with the case — deteriorated after Dillinger’s death precisely because Purvis had become too famous on his own account. Hoover’s model of the FBI was institutional: the Bureau was the hero, not individual agents. Purvis’s public prominence challenged that model, and Hoover managed the relationship accordingly.
Purvis resigned in 1935. His subsequent career was marked by the complicated afterlife of his role in the case — he was famous for it, but he could not quite capitalize on that fame in ways that satisfied him. His death in 1960, ruled a suicide by the same type of .45 caliber pistol he had carried as an FBI agent, was a quietly tragic end to a career that had peaked at a moment of genuine significance.
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## The Evidence as It Stands Now
The historical record for the John Dillinger fingerprint identification, assembled from the available primary documentation and the accessible secondary analysis, supports the following conclusions with varying degrees of confidence.
The postmortem fingerprint card dated July 22, 1934 — printed on a Chicago Police Department form at the Cook County morgue — is a contemporaneous document. Its chain of custody is imperfectly documented; multiple agents who were asked about who took the impressions could not recall specific details. This is a limitation of the record, not evidence of manipulation.