The Special Investigation Team of Crime Branch searched the office of one Nitin Nayak, a cement and real estate agent, in Margao town.
"The search was conducted as a part of the investigation into the illegal mining scam. We have seized some documents from his (Nayak's) office," a senior crime branch officer said.
The SIT is investigating several cases in the illegal mining scam.
Justice MB Shah Commission, which was probing the scam, had claimed the fraud to be worth Rs 35,000 crore.
The panel has accused Kamat of overseeing the scam, in which several bureaucrats and mining magnates are also alleged to be involved.