The culprit was an anonymous person.
The signature on this document is just 'John Doe'.
Archaic derogatory term for an unsophisticated person from the countryside. Not used in modern Japanese outside historical contexts.
In Edo-period documents, country folk were sometimes called 'Gonbee'.
太郎 is a common placeholder name for a generic male, similar to 'John' in English, but without the anonymous connotation of 権兵衛.
Standard kanji form for the placeholder name and archaic derogatory term.
Kana spelling is common in modern writing, especially when the kanji are not needed.
Originally a common male given name (Gonbee) in pre-modern Japan. Its use as a placeholder for an anonymous person likely arose from the name's perceived ordinariness. The derogatory sense 'country bumpkin' developed from the stereotype of rural people bearing such old-fashioned names.