Upon arrival, the police found that the fire had engulfed flats on the second, third, and fourth floors of the building. (Express Photo by Abhinav Saha) A day after nine people died in a fire which broke out at a residential building in Shahdara’s Vivek Vihar in East Delhi, the entire building was vacated on Monday and an investigation was launched by the Delhi Police to ascertain the exact cause of the blaze. Police officers said that they might also use 3D laser mapping technology, if required, to understand the circumstances under which the four-storey building caught fire. The police have used such mapping technology in major fire incidents earlier, including the Arpit Hotel fire in Karol Bagh and the Anaj Mandi fire in 2019. 3D mapping is a process of obtaining three-dimensional information about the site of an incident, especially when a structure has been severely damaged, with the help of softwares. According to a senior officer, the rear portion of the four-storey building was the most affected.…