A diver has died in an operation to recover the bodies of five Italians who drowned while exploring a deep underwater cave in the Maldives.The Italian tourists all failed to resurface while they dived 48 metres into a cave in Vaavu Atoll on Thursday. The group included Monica Montefalcone, a marine biology professor at the University of Genoa, and her 20-year-old daughter, Giorgia Sommacal.Three other adventure seekers on the trip — Muriel Oddenino of Turin, Gianluca Benedetti of Padua, and Federico Gualtieri of Borgomanero — also drowned during the dive.Mr Benedetti’s body was found near the mouth of the cave shortly after the incident, while rescuers believe the remaining four divers are inside the same cave, which consists of three large chambers connected by narrow passages.Mohamed Mahudhee, a member of the Maldivian national defence force, suffered decompression sickness while diving in a search for the remaining bodies on Friday.He died of the sickness after being transferred to hospital.“The death goes to show the difficulty of the mission,” Mohamed Hussain Shareef, the Maldives presidential spokesperson, told reporters.Carlo Sommacal, Ms Montefalcone’s husband and Giorgia’s father, said that “something must have happened down there”, given his wife and daughter’s extensive experience.Speaking to Italian TV, he described Ms Montefalcone as a highly disciplined and careful diver.Experts have said oxygen toxicity and sheer panic are possible factors behind the deaths of the five scuba divers.“It’s likely that something went wrong with the tanks,” Pulmonologist Claudio Micheletto told the Italian outlet Adnkronos on Thursday.“Death from oxygen toxicity, or hyperoxia, is one of the most dramatic deaths that can occur during a dive — a horrible end,” added Claudio Micheletto, the director of pulmonology at the University Hospital of Verona.Panic may also have played a part, according to Alfonso Bolognini, president of the Italian Society of Underwater and Hyperbaric Medicine.“Inside a cave at a depth of 50 meters, all it takes is a problem for a diver or a panic attack for a diver,” he said.“The agitation will cause the water to become cloudy and can impair visibility,” which can lead to “fatal errors”.But he stressed, “It’s not easy to say now what exactly may have happened at the bottom of the sea.”Diving at 50 metres exceeds the maximum depth recommended for recreational divers by most scuba certifying agencies, with depths beyond 40 metres considered technical diving that requires special equipment. The Italians were diving from a 36-metre luxury yacht, the Duke of York, when they disappeared.A sixth diver, a student at University of Genoa, had been geared up to dive when she changed her mind and stayed on board, becoming the trip’s sole survivor. The yacht’s operating license has been suspended pending an investigation, according to the Maldives Tourism Ministry.