A man has been detained after Prince Albert of Monaco's cousin was found dead over the weekend.
Antoine de Massy, 29, whose mother was the sister of the late Prince Rainer, was discovered in a park in the Larvotto district on Sunday.
Police arrested a man, reported to be Ukrainian by local media, on Monday morning and held him for questioning.
Monaco prosecutor Stéphane Thibault clarified to the Monaco Matin newspaper that the man is "at this stage merely a suspect/witness to events whose legal qualification remains to be determined, with the theory of an accident not being ruled out".
© Instagram / @antoinedemassyAntoine's family contacted police after he didn't show up at a family lunch on Sunday. Local reports said he had been seen with the man emerging from a nightclub in the early hours of the morning.
A post-mortem examination into the cause of death is ongoing.
Who was Prince Albert's cousin Antoine de Massy?
Antoine was the son of Christian de Massy, a sportsman, and Cécile Gelabale, Prince Rainer's sister. This makes Albert, who inherited the throne from his late brother in 2005, Antoine's first cousin once removed.
After studying international relations and affairs at Florida International University in Miami, Antoine developed a tech start-up app.
He was known as a keen tennis player and moved to Florida with his father to pursue the sport.
© Instagram / antoinedemassy"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," he told Vogue Italy in 2012.
Antoine said Novak Djokovic was his tennis hero "because he likes to joke on the field".
He said he hoped to one day become "world number one" in tennis, or "even making it into the top 20 wouldn't be bad".
Prince Albert and Princess Charlene's tribute
The royal couple announced news of Antoine's death on Monday.
Releasing a poignant statement, they said: "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.
© Getty"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."
Albert married former South African Olympic swimmer Charlene Wittstock in 2011, and the couple shares 11-year-old twins, Prince Jacques and Princess Gabriella.
