The remains of the 63-year-old man who owns the flat and a 54-year-old woman, who works as a cleaner, were found after a security guard alerted the authorities to a foul smell. Firefighters then broke down the door.
Eastern District Detective Chief Inspector Kong Sze-wan said officers were still looking into the relationship between the two, as well as the cause of death.
She said their preliminary findings are that that the pair had been dead for three to seven days. They say there were no signs of injuries, or that anyone had broken into the property.
There was also no sign of any suicide note.