The top two floors of Stephen Court, gutted in a major fire, were constructed illegally, city police commissioner Goutam Mohan Chakraborty said on Wednesday.
"The fifth and sixth floors of the building were constructed illegally. These were later regularised," he told reporters, adding that the promoter who built the two floors was absconding after Tuesday's blaze.
The police and fire brigade personnel had faced difficulties in conducting rescue operations inside Stephen Court as they were not provided the building plan, Chakraborty said.
"We had asked the building association president for a plan of the building and a list of tenants, but these were not provided to us. If we had the list, we could have saved some more people," he said.
Chakraborty said a number of people tried to escape through the roof of the building, but could not do so as the collapsible gate to the roof was locked.
Meanwhile, fire brigade sources said the fire could have been possibly caused by a leaking power cable of the building's elevator.