The ransom note carried fingerprintsSourced
A brewer was kidnapped in 1933.
A ransom note changed the investigation.
After US brewery executive William Hamm Jr. was kidnapped and released, FBI investigators used silver nitrate to reveal latent fingerprints on ransom notes. The prints linked the notes to the Barker–Karpis gang, an early success for the method on material that could not be dusted normally.
The paper carried
more than a demand.
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William Hamm Jr. · Wikimedia contributors
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Reviewed: 2026-10-01