A man stabbed three people including two children over a domestic dispute in a house at Godakawala late last night, the police said.
The police said that one child had died in the house while the woman, the mother of the two children, and the other child were admitted to hospital in serious condition.
The other child had died in hospital. The children who were killed were aged 5 and 12, the police said.
Investigations revealed that the man was having an illicit affair with the mother of the two children.
The two children had seen the man with their mother in bed last night while her husband was away.
Angered by the children seeing what he was doing the man stabbed them and the woman.