Police arrested a man on suspicion of killing his father and wounding his mother yesterday, just a day after officers detained another man suspected of murdering and butchering his elderly parents.
The 18-year-old was arrested at his home in a Yuen Long village on suspicion of stabbing his father to death and attacking his mother.
Police also arrested a 19-year-old friend of the man.
A source at the scene said a fight broke out after the father sought to stop his son playing computer games.
On Friday, the dismembered remains of an elderly couple were found in a Kowloon flat. Heads were discovered in a refrigerator while body parts were contained in moisture-proof boxes. The couple's younger son and a friend have been arrested in connection with the killings.
Police are investigating whether the suspects in the Yuen Long case were influenced by reports of the earlier crime, which is believed to have occurred on March 1. Officers will also consider whether the suspects were affected by drugs or alcohol.
"We are investigating the motive," said Won Mee-yee, officer in charge of the Yuen Long district crime squad.
"When we found the couple, they were covered in blood and there were cuts all over their bodies."
Police arrived at the scene after receiving a report from villagers in Wing Ling Nei, Pat Heung, at 3.20am that a dispute had broken out.
A 30cm knife was found at the scene, a 350 sq ft flat in which the victim, who was 50 years old, and his Filipino wife, 39, lived with their son.
The flat had one bedroom, which the son shared with his parents, said a source close to the investigation.
The victim was declared dead on the way to hospital. His unconscious wife was taken to Tuen Mun Hospital and remains in a serious condition. She is being treated for wounds to her neck and arms.
The 19-year-old arrested was also seriously injured and is being treated at the same hospital.