The former head of Ukraine's intelligence service died while diving in the Egyptian Red Sea resort of Dahab on Friday. Despite a diving instructor's attempts to save Victor Hvozd, 62, he died after attempting to swim quickly up to the surface from a depth of 40m. Egypt's public prosecution on Saturday said the cause of death was overexertion. A close friend of Hvozd’s, who witnessed Friday's accident, said he did not suspect foul play, an opinion corroborated by the Egyptian diving instructor. Hvozd was formerly chairman of Ukraine's Foreign Intelligence Service and had also held senior defence intelligence positions. His friend told police that while both men were diving, Hvozd began swimming up to the surface very quickly, while his friend, an experienced diver, tried to stop him, fearing that he might hurt himself. When Hvozd reached the surface, the Egyptian diving instructor saw him yank his diving mask off his face and struggle to breathe. His friend soon resurfaced and helped the diving instructor take Hvozd to the beach to offer him assistance, Mostafa Ahmed, a diving instructor based in Dahab, told <em>The National</em> that when divers are in the water, they are breathing compressed air that contains nitrogen, which then goes into their body tissue. “Experienced divers know to ascend to the surface slowly to give their bodies time to decompress from the nitrogen. But if they ascend too quickly, nitrogen bubbles form in the body which can cause nerve damage in mild cases. In extreme cases, it can cause paralysis or death if the bubbles are in the brain,” he says. While this might be a problem for some less experienced divers, it should not have been a problem for Hvozd, who reportedly had an internationally accredited diving certificate that permitted him to dive to a depth of up to 100m Despite the efforts of Hvozd’s friend and the nearby Egyptian diver, he died in the ambulance on his way to hospital. His body was later taken to the morgue where an autopsy was performed. The Ukrainian embassy was notified about the incident on Friday and one of their officials arrived in Dahab to oversee the investigation. The diving equipment used by Hvozd was also taken by security officials to be analysed for faults and to ascertain whether it was adequate to use at depth. Investigations are still under way. Though he was a high-ranking intelligence officer in his home country until his resignation in 2016, Hvozd had been a long-time resident of Dahab, a resort well-known for its Red Sea diving.