Prince Albert’s cousin Antoine de Massy, 29, found dead in Monaco

Mr De Massy was the grandson of Princess Antoinette, the elder sister of the late Prince Rainier III, making him a first cousin once removed of Monaco’s reigning sovereign, Prince Albert II.

His father was Baron Christian de Massy, and his mother was Cécile Gelabale.

Monaco’s prosecutor’s office confirmed that the cause of death has yet to be established.

“All hypotheses are on the table, including that of a simple accident,” the prosecutor’s office stated.

Concern was first raised when Mr De Massy failed to appear at a family lunch on Sunday, leading a relative to contact Monaco’s Public Security Department. His body was later located in a green space behind Villa Sauber, a Belle Époque landmark situated along Larvotto Boulevard.

Investigators reviewed surveillance camera footage from the area and identified a man near the scene.

He was subsequently arrested and remained in custody as of Monday evening, though authorities have not confirmed whether he is being treated as a suspect; it is possible he may simply be a witness.

Monaco’s prosecutor general, Stéphane Thibault, told local newspaper Monaco-Matin that an inquiry had been opened “to determine the cause of death.” Officials have stressed that no line of investigation has been ruled out.

Prince Albert and Princess Charlene broke their silence on Monday with a formal statement from the Palace.

“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,” it read.

The couple said they shared in the sorrow felt by his family and those close to him, offering “their sincere condolences at this painful time.”

The Palace also acknowledged Mr De Massy’s sporting passion, noting that as a devoted tennis player, “he was part of a family history closely linked to the sport in the Principality.” In a 2012 interview with Vogue Italia, Mr De Massy himself described Prince Albert as his first and greatest supporter.

Mr De Massy took up tennis at just three years old, with his father introducing him to the sport. He subsequently relocated from Monaco to Miami to pursue his training while continuing his education in Florida.

Speaking to Vogue Italia in 2012, he declared that his dream was “to become number one in the world,” before adding: “Even in the top 20 wouldn’t be bad!” He also harboured hopes of representing the principality at the Olympic Games.

Tennis ran deep in Mr De Massy’s bloodline.

His aunt, Elizabeth-Ann de Massy, served as head of both the Monte-Carlo Country Club and the Monegasque Tennis Federation until she died in 2020.

Her daughter, Mélanie-Antoinette de Massy, has since taken charge of both organisations, as well as the prestigious Rolex Monte-Carlo Masters tournament.