At least nine people were killed and 18 injured after they were trapped in a burning factory in the eastern Indian city of Calcutta early Wednesday, fire officials said. The fire broke out in a leather factory on the third floor of a building at 02:30 a.m. (2100 GMT Tuesday), said West Bengal Director of Fire Services Gopal Battacharjee. The building had been locked from the outside, he said. Fire engines extinguished the fire and removed nine bodies from the site, Battacharjee said. The injured were taken to local hospitals. Battacharjee said an investigation had been launched to determine what caused the fire and why the people were locked in the building at that time. However, it is not uncommon for workers to sleep at their factories or for factories to employ round-the-clock shift workers.