Antoine de Massy, a 29-year-old relative of Monaco's ruling family and a cousin to Sovereign Prince Albert II, was found dead in the principality on Sunday, October 25, 2026. Following the discovery of his body near Boulevard du Larvotto, judicial authorities opened an official investigation into the cause of death and placed one individual into police custody on Monday morning, October 26, after reviewing local security camera footage.

The Prince's Palace confirmed the death on Monday in an official statement expressing the royal family's grief, according to HOLA! USA. While law enforcement officials continue to question the detained individual—whose custody was extended by 24 hours—prosecutors have emphasized that the person's exact role remains under review and that all possibilities, including an accidental death, are being considered.

Timeline of the Discovery and Investigation

The search for the 29-year-old began on Sunday afternoon after he failed to appear for a midday meal. According to local reporting cited by HOLA! USA and Monaco-Matin, a worried family member contacted Monaco's Public Security department to report his absence, prompting an active search by authorities.

Accounts vary slightly regarding the exact timing and description of the location where his body was recovered. According to France 3 Provence-Alpes-Côte d'Azur, which cited a Monday statement from Monaco's Prosecutor General, Public Security officers located de Massy's body in the early evening on Sunday in a park area below Boulevard du Larvotto. Meanwhile, HOLA! USA reported that the body was discovered on Sunday night in a landscaped garden behind Villa Sauber, one of the principality's prominent cultural landmarks along the same boulevard.

Following the recovery of the body, the case was handed over to the judicial police to establish the exact cause of death. Investigators immediately began examining video surveillance from the surrounding neighborhood. According to the prosecutor's statement reported by France 3 Provence-Alpes-Côte d'Azur, the footage revealed that a man had come into contact with de Massy while he was still walking along Boulevard du Larvotto.

Questions Surround the Detained Individual's Role

On the morning of Monday, October 26, police identified and arrested the man seen on the surveillance cameras. Authorities subsequently extended his police custody by 24 hours to allow for further questioning.

While some early media summaries described the detained person as a suspect, official statements reported by local outlets present a more cautious picture. Speaking to local press in comments cited by HOLA! USA, Monaco's Prosecutor General explained the legal mechanics behind the detention: "We then had to modify the procedural framework in order to detain this person, place them in police custody and try to clarify the circumstances of the death."

According to Monaco-Matin, officials have not publicly clarified whether the individual in custody is considered a criminal suspect or simply a key witness who interacted with de Massy shortly before he died. Both Yahoo Entertainment and France 3 Provence-Alpes-Côte d'Azur noted that prosecutors are evaluating every hypothesis, explicitly stating that the possibility of a simple accident has not been ruled out.

Prince Albert II and Princess Charlene Issue Tribute

The sudden loss prompted an official message of mourning from the Prince's Palace on Monday. Prince Albert II, 62, the son of Prince Rainier III and Grace Kelly, and his wife, Princess Charlene, 48, publicly acknowledged the death of their young relative and highlighted his dedication to athletics.

"Their Serene Highnesses Prince Albert II and Princess Charlène were saddened to learn of the death of Antoine de Massy, aged 29, the grandson of Princess Antoinette, the elder sister of Prince Rainier III," the royal couple stated, as reported by Yahoo Entertainment and Nice-Matin. "A keen tennis player, he was part of a family history closely linked to the sport in the Principality. Their Highnesses share in the grief of his family and loved ones and offer them their sincere condolences at this painful time."

A Royal Lineage Tied to Monaco's Sporting History

Born to Baron Christian de Massy and Cécile Gelabale, Antoine de Massy occupied a notable branch of the Grimaldi extended family tree. Because his father, Christian de Massy, is the son of Princess Antoinette and the first cousin of Prince Albert II, Antoine was the sovereign prince's first cousin once removed—often referred to in French and regional press as a second cousin or "petit-cousin."

As the palace statement noted, de Massy's background was deeply intertwined with Monegasque sports and civic institutions. According to HOLA! USA, his grandfather, Alexandre-Athenase Noghès, was a prominent Monegasque tennis player who married Princess Antoinette. Furthermore, Yahoo Entertainment noted his family connection to Anthony Noghès, the founder of the Automobile Club de Monaco. On the tennis side, Antoine's late aunt, Elizabeth-Ann de Massy, presided over both the Monte-Carlo Country Club and the Monegasque Tennis Federation until she died in 2020. Her daughter—Antoine's cousin, Mélanie-Antoinette de Massy—currently heads both organizations as well as the Rolex Monte-Carlo Masters tournament.

Following in his relatives' footsteps, Antoine began playing tennis at the age of three after being introduced to the game by his father. He eventually relocated from Monaco to Miami, Florida, to balance his academic studies with rigorous athletic training that began at 8 a.m. each day. In a 2012 interview with Italian Vogue cited by Yahoo Entertainment and HOLA! USA, he expressed his admiration for tennis star Novak Djokovic and shared his aspirations to become the world's top-ranked player and represent Monaco at the Olympic Games.

"It was a difficult choice, but it's my choice: my father made it very clear to me that I had to give it my all from the start, and that once I made my decision, there was no going back," de Massy said in the 2012 interview.

Key Questions in the Ongoing Investigation

What have authorities said about the cause of death?

Officials have not yet disclosed a cause of death. Monaco's judicial police are currently conducting an investigation to determine how de Massy died, and prosecutors noted that all possibilities, including an accident, remain on the table.

Is the person in police custody considered a suspect?

Authorities have not labeled the detained man a suspect. The Prosecutor General stated that the procedural framework was adjusted to place the individual—who was spotted on security cameras near de Massy on Boulevard du Larvotto—into custody for questioning to help clarify the timeline and circumstances of the death.

Sources