The CBI started questioning Sheikh Shahjahan at its Nizam Palace office in Calcutta on Thursday while a two-member team of the central agency visited Sandeshkhali and scanned his house, office and other places as a part of the probe into the alleged attack on a visiting ED team on January 5.

In Sandeshkhali, with central forces in tow, the CBI team asked a state police officer to identify Shahjahan’s residence and then went to a plot in Akunjipara area to the strongman’s double-storey house fitted with several air-conditioners.

Entrances were closed off with iron gates. The CBI team couldn’t enter the building, but clicked photographs of it.

Then, the CBI team moved to Sheikh Shajahan Market, which he allegedly built by grabbing land in Sarberia village. Shahjahan visited the market complex office almost daily, bystanders told the team.

Shahjahan was brought to Nizam Palace around 9.30pm on Wednesday after a health check-up at ESI Hospital. At Nizam Palace, he was lodged in the room where Trinamul leaders Partha Chatterjee and Anubrata Mondal were lodged. Sources said he struggled to sleep and sought rice for breakfast but got ruti tarkari.

His grilling started at 11am on Thursday and lasted for hours with some breaks. The CBI seeks to know who Shahjahan called up on January 5.