As the first of the bodies of the 121 people killed in the Helios Airways plane crash on Sunday were buried in Cyprus yesterday, investigators became increasingly convinced that the cause of the accident lay in a problem with the aircraft’s air-conditioning and decompression systems, sources told Kathimerini. Experts from US manufacturer Boeing have ruled out the possibility that the aircraft was shot down by either of the two Greek air force jets which had been shadowing it before it crashed into the side of a hill in Grammatiko, sources told Kathimerini. The two F-16 planes had been scrambled to intercept the aircraft when Athens air traffic control declared it a «renegade plane» after it had failed to make contact with the crew. Post-9/11 regulations give authorities the option of shooting down a plane if they believe it has been taken over by hijackers and could pose a danger. Investigators are increasingly focusing the attention of their probe on a combined fault in the plane’s air conditioning and its electric decompression system. Initial theories had pointed to a drastic loss of air pressure, which starved the crew and passengers of oxygen. However, this explanation seems to have been disproved after coroners revealed that all of their tests so far have found that the people on board were alive, although maybe not conscious, when the plane hit the ground. Experts were yesterday intensifying efforts to find the three remaining bodies of the 121 killed, including that of the German captain. Investigators are also searching for the voice recorder from the black box in the cockpit, which could shed light on what was being said by the crew on board in the build up to the crash. The head of the Greek airline safety committee, Akrivos Tsolakis, told Kathimerini that the latter would be among the «most important» pieces of information from the probe into the most deadly air disaster to take place in Greece. The wife of the plane’s co-pilot, Charalambos Charalambous told Kathimerini that her husband had expressed concern about the state of the aircraft on many occasions and that he kept a record of the problems it developed in a diary, which she thinks he probably had on board with him. Sofia Charalambous also alleged that her husband had complained about poor relations with Helios management and the German pilot he flew with. Meanwhile, a row broke out yesterday between the chief coroner in Athens, Philippos Koutsaftis, who is leading the autopsies on the victims of Sunday’s crash and two coroners in Cyprus who criticized the way the probe is being handled. Marios Matsakis and Panikos Stavrianos said that Koutsaftis had been too quick to make statements, especially since the results of toxicology reports were not yet known. They were also critical of the decision to send back the bodies of 23 victims on Tuesday night to Cyprus for burial (three victims were buried yesterday) before the probe had been fully completed. Koutsaftis said the Cypriots’ claims were «provocative» and that the autopsies were being handled properly. He added that all the necessary samples had been taken from the bodies which had passed through the morgue, meaning that the relatives were free to bury their dead.