According to an Indian source: “A single Judge investigation committee and a Special Investigation Team (SIT) were formed by Tamil Nadu government to investigate the cause of the disaster. The major reason for this disaster was due to the carelessness of the builders in Chennai. The chief engineer handling the construction accepted his mistake and was fined by the police.”
Unfortunately the reasoning for the collapse was not given in detail. In this video the building shows a remarkable stiffness towards the end of the collapse. This contradicts the accusations that the building was prone to collapse at any time by its own self weight.