A 66-year-old woman and her 33-year-old son died while her husband and another son, were injured early this morning.

At about 12:30 am, Police received a report of a fight at a house in Sheung Wu Yiu on Tat Wan Road in Tai Po.

Police found all four people with stab wounds lying inside the house.

They were sent to the Prince of Wales Hospital and the Alice Ho Miu Ling Nethersole Hospital for medical treatment.

The woman and her 33-year-old son were later certified dead at the Alice Ho Miu Ling Nethersole Hospital. The husband, aged 78, and another son, aged 30, are in hospital, in critical condition.

Officers seized a knife with bloodstains at the scene.

Suspect found dead in a nullah

Meanwhile, Police are investigating a case in which the body of a 39-year-old man was found in a nullah on Tat Wan Road in Tai Po this morning.

At about 8.45 am, a passer-by reported to the Police that a man was found collapsed. Police located the man who was later confirmed dead at scene.

Initial investigations suggest the man has a connection with the murder case.

It is also believed that the man fell from Tolo Highway into the nullah and a post-mortem will be conducted on Monday to ascertain the cause of the man's death.

Post-mortem examinations will also be conducted on Monday to determine the cause of death of the woman and her son.

Tai Po District Crime Squad is investigating.