A post mortem examination's taking place today on the body of a baby boy who was killed in te Ardoyne area of north Belfast on Tuesday night.
A two-year-old girl's fighting for her life in hospital, after being seriously injured in the incident.
A 29-year-old woman was arrested on suspicion of murder and attempted murder, and remains in police custody.
It's understood the children's father returned home from England yesterday.
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