An 88-year-old man died at home after his mentally ill wife failed to get help and sat by his body for two days, police said.
The man, who slipped in the bathroom and hit his head, died from blood loss, officers believe.
His 77-year-old wife had not drunk or eaten anything for the two days when police found her.
The tragic case came to light only yesterday morning, when a nurse visited the couple at their 24th-floor flat in Chung Yuen House at Chuk Yuen North Estate, Wong Tai Sin.
Officers said the elderly woman could not answer the door and was too weak to shout for help.
The nurse called the couple's son, who raced to the scene and kicked open their front door at about 9.30am.
The man was found lying in blood on the floor in the living room, with injuries to his face. His wife was still sitting by the body.
"She was very weak," said Superintendent Tommy Tang Wai-keung, acting assistant commander of crime in Wong Tai Sin.
The woman was found to be suffering serious dehydration and was taken to Queen Elizabeth Hospital.
Initial examinations showed that the man had been dead for about two days, police said.
Officers believe that he slipped on the floor and hit his head against the toilet bowl in the bathroom on Sunday.
His wife told police that she had carried him out of the toilet and pressed the emergency button of a device connected to the Senior Citizen Home Safety Association's call centre.
But officers found the device in her bedroom and the association, which runs the Personal Emergency Link Service for more than 80,000 elderly people, said no records indicated that she had pressed the button.
The elderly couple, who both had difficulty walking, have three children but lived alone.