Police believe the deaths of three people in Ballymena on Monday involved a double murder.
A 41-year-old man, a woman aged 39 and an eight-year-old girl were found in a house in the Old Cullybackey Road area.
Superintendent William Calderwood, from the Police Service of Northern Ireland (PSNI), said they were from the same family and called it a "shocking scene".
The adults are believed to have originally been from Poland.
Superintendent Calderwood said they were waiting for the results of a post-mortem but "a strong hypothesis is that this was a double murder followed by a sudden death".
Police are not looking for anyone else and specialist officers are supporting relatives and liaising with the Polish consulate.
Flowers were left outside the property this morning and a pair of child's sandals were still hanging on the washing line.
Anyone with CCTV or dash-cam footage that might be relevant is asked to contact police on 101.
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"My heart goes out to the relatives in the Ballymena area and to those in Poland," said North Antrim MP and TUV leader Jim Allister.
"I am also mindful of the school friends of the child and the distress they will suffer," he added.
"The gruesome scene with which the first responders and forensic officers had to deal is a reminder of how hard their job can be. We are grateful for all they do.
"Even as the shock subsides over coming days there will be a lasting effect in the neighbourhood of this awful event."
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