The victim, 58-year-old Duraiswamy of Sankari Vadugapatti had gone missing after he left his house on December 17 and his wife had lodged a complaint with the police.
Some persons fishing in the river found his severed head, hands and legs in the Cauvery river bed at Kumarapalayam this morning and reported the matter to police.
Duraiswamy is stated to be a relative of former DGP K Ramanujam, now an advisor to the government after his retirement last month.
Duraiswamy had been kidnapped, murdered and his body cut into pieces and dumped, by henchmen over a dispute with another person for not sharing the profit in a land deal, police said.