Poison may have been used by a mother to kill her child before committing suicide, it emerged today.
The bodies of Madeleine O'Neill and daughter Laura (9) were found by a friend at their bungalow in the Manse Road in Carryduff before midnight on Tuesday.
The bodies of two pet dogs were also discovered at the detached house in Co Down.
It is believed Mrs o'Neill, whose marriage broke-up earlier this year, suffered from bouts of depression. Her husband was not at the property and police confirmed they were not looking for anyone else.
As forensic experts searched the house for evidence, sources disclosed that a poisoning or drug-overdose theory was being probed by detectives.
Post mortem tests have taken place, but police have not revealed the results.