The air conditioning system at a hotel where a British couple died in unknown circumstances while on holiday in the Egyptian Red Sea resort of Hurghada is sound, the public prosecutor said on Saturday, citing a report by engineering experts. The prosecutors office said it was still waiting for a medical report to determine what caused the death of John and Susan Cooper who passed away hours apart on Tuesday while staying at the Steigenberger Aqua Magic Hotel. Britains Thomas Cook, which organised the trip, said on Friday it had received further reports of illness among guests at the hotel, without elaborating. The hotel said on Friday that there had not been a rise in cases of illness. In a statement, the Egyptian public prosecutor said that engineers assigned to check the room where the deceased couple had been staying concluded that "all equipment was sound and that there was no leakage or emission of any poisonous or harmful gases". "All equipment was working properly and had no faults," it added. But the statement said the prosecution was still awaiting the results of a forensic analysis of samples taken from the couple, and promised to issue a detailed report. Egyptian officials said on Friday that both deaths were from heart failure, but the public prosecutor said the cause was still not yet clear.