A 10-member CBI team searched the houses of Karapudi Mahesh, Swastik Nagaraj and Somasekhar, who runs a transport firm, all aides of Reddy, CBI sources said.
Raids are being conducted in Sandur Taluk of mine-rich Bellary district also, they said.
CBI had yesterday filed an FIR on the illegal export of iron ore from Belikeri port in Uttara Kannada district in Karnataka, the investigation of which has been entrusted to it by the Supreme Court.
The CBI had earlier filed a criminal case on the directions of the Supreme Court in October last year against Reddy and others under various IPC sections, Prevention of Corruption Act, Indian Forest Act and Mines and Minerals Development and Regulation (MMDR) Act 1957.