Officers said the man had also attacked his two sons, 15 and 18, and killed the family’s dog in their Whampoa Garden home.
At a press briefing, chief police inspector Wong Sai-kwan said the man, 49, had allegedly used a knife to attack his wife, 48, who was asleep in the bedroom. He then attacked his two sons before locking himself in the kitchen and committing suicide.
The younger son made a report to the police.
The two teenagers also suffered knife wounds and were rushed to Queen Elizabeth Hospital for treatment.
Police said they have not been able to talk to the pair yet.
Initial investigations showed that no one from the family had any history of mental problems, nor had any incidents of domestic violence been reported.
Wong said the husband ran an IT business that was in financial difficulties in recent months, which might have triggered the tragedy.