United States v. Mangan

Frank Mangan (defendant) was charged with tax fraud for filling out fraudulent returns for other people. To prove the fraudulent returns were in Mangan's handwriting, the prosecution offered his own past tax returns and personnel-file forms as comparison samples, though no witness testified Mangan had actually written those comparison documents himself. A handwriting expert testified that the same distinctive block-capital-letter style appeared across Mangan's tax returns, his personnel forms, and the fraudulent returns, and that the same person had filled out both the personnel forms and the fraudulent returns; Mangan objected to using his own tax returns and personnel forms as authenticated handwriting samples, but the trial court admitted them, and he was convicted.