Barmer/Jaisalmer, Oct. 25 -- A short-circuit in the air conditioning unit led to the massive fire in a private sleeper bus on the Jaisalmer-Joshpur highway on October 14, in which 26 people were killed, according to the forensic investigation in the accident. Jaisalmer superintendent of police Abhishek Shivhare confirmed the findings and said the investigators ruled out the presence of any flammable or explosive material inside the bus. "The report clearly indicates that the fire originated from the AC wiring and spread due to lack of proper safety measures. It was a preventable tragedy caused by negligence," he said. The report made public on Friday also said the fire began on the roof of the bus and gradually spread out through the cabin. The forensic team from Jaipur and Jodhpur, which inspected the site on October 15, found that the AC unit installed on the roof was connected directly to the engine, leading to fumes entering the cabin, said the report. As the fumes spread inside, many passengers began to suffocate and lost consciousness . When some passengers tried to break the windows to escape, air rushed in and intensified the flames, which engulfed the entire bus within seconds, said the report. Investigation also revealed multiple violations of safety norms. The AC wiring was directly connected to the engine which helped fumes enter the cabin, and the material used in the bus body were not fire-resistant. The police have arrested the bus owner, the driver, and Manish Jain, the owner of the workshop that built the bus body, on charges of gross negligence and safety violations....