This was precisely what happened with Dillinger’s postmortem prints. The acid damage to the central areas made classification difficult. But the examiner examining those prints was not dependent on classification alone. The surviving peripheral ridges showed sufficient minutiae — ridge endings, bifurcations, enclosures, and other characteristics — to compare against the known Dillinger record. The match was established from those surviving areas.
The criminal operators offering print removal services — the underground physicians and surgeons like Loeser who performed these procedures — did not appear to understand, or did not explain to their clients, this distinction between pattern classification and minutiae comparison. They sold a procedure that attacked the classification feature without eliminating the comparison feature. The identification process they were trying to defeat was more robust than their attack on it.
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## The Chain of Custody Question: Who Printed the Body
One unusual aspect of the Dillinger identification record is the documented uncertainty about who actually took the postmortem fingerprint impressions.
The fingerprint card in the FBI’s records associated with the postmortem identification is dated July 22, 1934. It is printed on a Chicago Police Department form, not an FBI form. The notation “Dept. of Fe” on the card was crossed out and replaced with “Justice Print.” The signature of whoever took or certified the impressions is illegible.
A subsequent investigation into this chain of custody — examining what FBI records showed about who took the impressions and when — found that multiple agents who were asked could not recall the specific details. The chain of custody documentation that would normally accompany a fingerprint card of this significance was incomplete.