The man was identified as Azami Mohamed, 38, a civil servant from Kuala Krai.
A police spokesman from the Sungai Golok police station said the body was found by residents living near the river floating face-down close to a jetty near Charoenkhet Road about 9am local time.
The spokesman said a police team went to the scene to recover the body before sending it to the Sungai Golok district hospital.
“Initial investigation revealed that the man was hit with a hard object on the right side of the head, leaving a big wound,” said the spokesman. The spokesman said police are investigating the case including the motive behind the killing.