Pol Maj Gen Apichart Boonsriroj, said police want to establish the cause of death as they believe he died of mysterious circumstances.
Viacheslav Kolbunov was found dead with his dog on Friday afternoon. Both were believed to have been dead at least six days.
Pol Maj Gen Apichart said police have collected fingerprints and traces of DNA for examination.
A preliminary police investigation found no evidence of a break-in and no indications that the man had died of unnatural causes.
Viacheslav’s Dog that died had suffered from a kidney problem, according to a local veterinarian.
Neighbours said the Russian man had lived alone in the house for about ten years. He had a son who worked in China and occasionally came to Kok Samui to visit.
Pol Maj Gen Apichart said Viacheslav’s body would be sent for a forensic examination to establish the cause of death.
No mention was made of what might have caused the dog’s death.