His son, Somsak Chaikhamchan, 50, told police that his father, Rien Chaikhamchan, had disappeared two days before.
His body was found floating in a canal about two kilometres from his village.
The son said the old man liked to walk to his rubber plantation about three kilometres away from the house and stay at a hut there during the day before walking back home as a daily routine. After he did not return on Monday, Somsak and other relatives searched for Rien until his body was found.