Disruption in power supply allegedly left five patients on life support dead at Government Rajaji Hospital here, police said Wednesday. However, Dean Vanitha said the patients, who were in the ICU, died of natural causes. The dean said it was a sheer coincidence that the electricity supply was disrupted at that time. On the other hand, relatives of the deceased alleged the ventilators were not working properly. Refuting the charges, Director (Medical Education) Dr A Edwin Joe said the ventilators were alright as these had built-in batteries. Among the five who died were Malliga (58), Palaniammal (60) and Ravindran (52). Relatives of the patients also staged a dharna. Deputy Commissioner of Police Sasimohan, dean Vanitha and medical superintendent Raja held talks with the bereaved families.