The blaze broke out on December 9 at a seven-storey building in central Jakarta rented by drone operator Terra Drone Indonesia, where employees became trapped inside as smoke spread through the structure.
Police said the fire started on the ground floor, where the company stored drones and equipment, including lithium batteries.
According to eyewitnesses, one 30,000 mAh battery fell from a four-layer stack, causing sparks that ignited the blaze, Central Jakarta police said.
The storage room lacked proper ventilation and fire resistance and also housed a generator that produced heat, Susatyo Purnomo Condro, head of the Central Jakarta police, told reporters on Friday, as quoted by state news agency Antara.
Interior Minister Tito Karnavian said employees ran upstairs to escape the flames but were trapped because the building had no emergency exit.
