The actor who returned from Chennai by 9 pm last night was questioned by IT officials at his residence at Panampilly Naagar here till 3 am today, top IT sources told PTI.
Mammooty "cooperated fully with the officials", the sources said.
Large number of Mammooty fans had gathered at the airport to express solidarity with the actor, when he arrived here with his wife from Chennai last night.
Some more searches will be conducted at his house in Chennai after the actor returns there, R Mohan, Additional Director General, Income Tax told PTI.
"We have taken some documents pertaining to landed properties. It is too early to comment now. A final picture would emerge by Wednesday, he said.
IT Officials had yesterday raided the offices, residences, and business establishments of Mammooty and Mohanlal at various places in Kochi, Thiruvananthapuram, Chennai, Bangalore and Udhagamandalam (Ooty).
The raids would not be held today, the sources said. Mohanlal, who is in Rameshwaram in connection with a shoot, would be questioned at Chennai on July 25 and in Kochi on July 26, Mohan said.
The two actors were under I-T scanner for the past few months and the raids, as per Section 132 of the Income Tax Act (relating to search and seizure), came after ''specific information'' that they had wealth disproportionate to their known sources of income, the sources said.