BENGALURU: The search for 31-year-old cybersecurity professional Advait Upadhyay entered its fourth day Monday, with nearly 100 personnel from National Disaster Response Force (NDRF), State Disaster Response Force (SDRF), forest department and police scouring the treacherous slopes of Shivagange Hills in Nelamangala taluk of Bengaluru Rural district.The operation took a crucial turn after high-resolution drones deployed by search teams captured what appeared to be a body trapped amid dense vegetation at the base of Shantala Drop, one of the steepest and most dangerous cliff points on Shivagange.However, persistent rain, slippery rocks and the treacherous terrain prevented rescue personnel from reaching the location to verify the sighting.Advait, an IIT graduate residing in Kadugodi, went missing Friday after setting out on a solo trek to Shivagange.His disappearance initially puzzled investigators after his rented motorcycle was found parked at the foothills, while his mobile phone was switched off and its last known location was traced to an area away from the regular trekking route.CCTV footage from the foothills showed Advait parking the motorcycle and beginning his ascent around 7.30am. Before proceeding further, he reportedly sent a selfie to his fiancée, Prapti Chauhan, from the hilltop.His phone was switched off shortly afterwards, leaving his family and investigators with few clues about his subsequent movements.