A bedridden woman and her son, who quit his job about 10 years ago to take care of her, died in a family tragedy.
They were found unconscious in their flat in Sham Shui Po and declared dead in hospital.
Crime squad officers are investigating whether foul play was involved in the death of the 76-year-old woman and her 56-year-old son.
Police and paramedics were called to the family's flat in Shing Tin House, on the Pak Tin Estate, at about 10.15am when her 80-year-old husband found the two in a bedroom.
Police said the woman was in her bed and her son was lying unconscious on the floor beside her bed. They were taken to Caritas Medical Centre, where they were declared dead before 11am.
Police said the son had woken up and gone to the toilet at about 9.30am before he went into the bedroom to check on his mother.
'The father told our officers that his wife was asleep when he woke up at about 7.30am. He then went to the living room and listened to the radio,' a police officer said.
The officer said an initial examination found no apparent wounds on the victims and there were no signs of a struggle or fight.
'Crime squad officers are still investigating whether foul play was involved in their deaths. At this stage, the cause of their deaths remains unknown. An autopsy will be carried out,' the officer said.
Another officer said the victims suffered illnesses and had been taking medication.
'The elderly woman was a diabetic and also suffered other chronic illnesses, and her son always complained of headaches,' the officer said. 'We have taken their medicine for examination.'
But the officer said the initial investigation was able to confirm that neither of them had a history of heart problems.
Four people lived in the flat: the woman and son, her husband and a younger son who was not at home at the time.
The 56-year-old man was described by police as a 'good and responsible' son. 'He quit his job as a factory worker about 10 years ago to look after his bedridden mother,' the officer said.
Detectives from Sham Shui Po police station are investigating.