A man whose marine biologist wife perished during a diving expedition in the Maldives fears 'something must have happened down there' as mystery surrounds the five fatalities.The group, from Italy, had set off to explore the Vaavu atoll on Thursday morning but never resurfaced.The decision to try to reach the cave has been questioned by experts, with three key elements raised:Firstly, a weather warning was in place. High winds whip up waves, which in turn could dislodge sand and dirt, obscuring visibility.Secondly, tourists are not meant to dive below 30 metres. The cave is around 60 metres below the surface.And finally, the cave itself is notoriously difficult to reach. Maldives government spokesman Mohamed Hussain Shareef said that the cave 'is so deep that even divers with the best equipment do not try to approach.''There will be a separate investigation into how these divers went below the permitted depth, but our focus right now is on the search and rescue,' he added.One of the victims is 51-year-old Monica Montefalcone, a respected marine biologist, TV personality, and professor of Tropical Marine Ecology and Underwater Science at the University of Genoa. Her 22-year-old daughter, Giorgia Sommacal, also died.Carlo Sommacal, Montefalcone's husband and Giorgia's father, broke his silence following their deaths. Devastated Sommacal insisted that 'my wife is among the best divers on earth,' and said she wouldn't have put anyone in the group in danger.