According to Nokorwat News (Graphic Warning!)

Foreigner found dead in the room of a rental house; death cause unknown.

Sihanoukville:
A foreigner was found dead in the room of a rental house but the dead cause is still unknown. The dead body was found in the morning of January 2 2016 in Group1, Phum3, Sangkat4, Sihanoukville.

Authorities identified the deceased as Croy James Robert, male, 74 years old, American national, passport number XXXXXXXXX, visa number XXXXXXXX, valid till June 6 2015.

According to the police the body of the deceased didn’t show any scars related to a murder. The same police has no idea about the cause of death.
2 other sources said that the victim died because of heart problems and exhaustion. Nobody knew and nobody helped.

Currently the corpse is kept in the morgue of the Provincial Hospital awaiting further instructions from the embassy.

Read more here.