Giovanna De Grandis was born in Rome. She was working as a laundress when she was recruited to the organization of
Gironima Spana
{{One source, date=February 2022
Gironima Spana (1615-5 July 1659) was an Italian poisoner and astrologer.Monson, Craig A.: The Black Widows of the Eternal City: The True Story of Rome’s Most Infamous poisoners' She was the central figure in the ...
, who trafficked in lethal poison. De Grandis was an important member of the Spana organisation: she had direct contact with Spana and was one of the few of Spana's associates whom Spana entrusted the task to not only sell, but also to manufacture poison. She and Spana herself manufactured the poison using arsenic acquired by the priest Don Girolamo, since apothecaries did not sell arsenic to women.
De Grandis was arrested in flagrante on 31 January 1659 and imprisoned in the Papal prison at
Tor di Nona
The Tor di Nona is a neighborhood in Rome's ''rione'' '' Ponte''. It lies in the heart of the city's historic center, between the ''Via dei Coronari'' and the Tiber River. Its name commemorates the Torre dell'Annona, a mediaeval tower which once s ...
, where she was interrogated by the Papal authorities under lieutenant governor Stefano Bracchi. She confessed her guilt on 1 February, and started to name the names of her accomplices and clients. Her testimony was essential to the Spana Prosecution. She personally reported the central figure Gironima Spana herself.
On 5 July 1659,
Gironima Spana
{{One source, date=February 2022
Gironima Spana (1615-5 July 1659) was an Italian poisoner and astrologer.Monson, Craig A.: The Black Widows of the Eternal City: The True Story of Rome’s Most Infamous poisoners' She was the central figure in the ...
Campo de' Fiori
Campo de' Fiori (, literally "field of flowers") is a rectangular square south of Piazza Navona in Rome, Italy, at the border between rione Parione and rione Regola. It is diagonally southeast of the Palazzo della Cancelleria and one block north ...