Sooraj, former Land Revenue Commissioner, was questioned in connection with the Kalamassery land grab case, CBI sources said.
CBI, on June 3, had arrested Salim Raj, Chandy's former gunman who is under suspension, and nine others in two land grabbing cases involving properties worth more than Rs 425 crore located in Kadakampally in Thiruvananthapuram and Kalamassery here.
The IAS officer, who was also the PWD Secretary, was suspended in November last year for allegedly amassing wealth disproportionate to his known sources of income.
Last week, the Kerala High Court had set aside his order.
Allegations had been levelled against Sooraj that he had cleared revenue procedures to help the accused, who are reported to be his relatives, grab land worth crores of rupees.
Sooraj had denied all charges and said he acted based on reports from other officials.