"The team has arrived and has started investigations to find out the cause of the fire which broke out yesterday," official sources said.
A separate inquiry was being made at the district level to ascertain the reason for yesterday's fire which broke out while Banerjee was in the bathroom.
The fire services and the district police were also ascertaining the cause of the fire.
The police had said that the AC in the room caught fire while Banerjee was inside the washroom. She had felt uneasy after inhaling smoke and shouted for an aide who came to her rescue and pulled her out of the smoke-filled room.
WBPCC chief Adhir Ranjan Chowdhury said that it was surprising that no action was taken against the officials who were in charge of the chief minister's security.
Referring to the allegation of a conspiracy, Chowdhury, the Union Minister of State for Railways, said only a CBI investigation could throw light on it.