Police in the Irish Republic have arrested a 31-year-old man after two women and two children were found dead in a house in County Limerick.
It is believed they were stabbed. One of the women in their 20s is thought to be the mother of the children, a three-year-old boy and a five-month-old girl.
Police were called to the house in Newcastle West at about 1350 GMT on Tuesday.
Meanwhile, two children and their father have died in County Cork.
John Butler died when his car crashed near Ballycotton on Tuesday morning. His daughters, Zoe, seven, and two-year-old Ella, were later found at his home.
He died when his car burst into flames after hitting a tree.
Concerns were raised after Zoe did not turn up at a local primary school.
Police went to the home of Mr Butler, who was in his 40s, and discovered the bodies of the two girls inside.
It is not yet known how they died.
It is understood the children's mother had left for work in Cork city at about 0730 GMT, just over two hours before the car crash.