Overview
- Family members reported Antoine de Massy missing after he failed to attend a traditional Sunday meal, and his body was found hours later on Sunday, October 25 in a green area along the Boulevard du Larvotto.
- The Monaco public prosecutor has opened a formal inquiry to establish the cause of death, which remains undetermined pending forensic results.
- Police reviewed surveillance footage that identified a person seen near the discovery site and that person was detained and is being questioned but has not been formally charged.
- The Princely Palace publicly offered condolences from Prince Albert II and Princess Charlène, and reporting notes that de Massy was a grandson of Princess Antoinette, a former youth tennis talent, and a co‑founder of a local tech venture.
- Local media have reported unconfirmed details such as a nightclub sighting and a possible fall from the nearby Voie rapide; officials have not verified these accounts and investigators say they are continuing forensic work and witness interviews.