Monaco police arrest a Ukrainian man seen on CCTV after Prince Albert's cousin, 29, is found dead in a garden

Antoine de Massy, 29, a keen tennis player and tech entrepreneur, was a first cousin once removed of Monaco's Prince Albert II. He was last seen leaving a nightclub in the early hours of Sunday, visibly unsteady, before his body was discovered in the garden of Villa Sauber, a Belle Époque landmark on Larvotto Boulevard.

When De Massy failed to show up to a family lunch on Sunday, a relative alerted Monaco's Public Security Department.

Prince Albert II and Princess Charlène said they were 'saddened' and offered their condolences to his family.

De Massy had trained at the Nick Bollettieri Tennis Academy in Florida and recently co-founded a tech firm called Instant Tech.