This article was reproduced with the kind permission
of the British Broadcasting Corporation
17 November 2007, 18:59 GMT
Arthur McElhill, Lorraine McGovern and their five children died in the blaze early on Tuesday. It is understood Mr McElhill is a suspect.
Post mortem examinations have been carried out on the bodies.
All seven deaths are being treated by the police as murder. Police said petrol had been scattered around the house and it had been set alight.
Meanwhile, Deputy First Minister Martin McGuinness said the authorities will have to learn lessons from the tragedy.
Interviewed for the BBC's Inside Politics, he said a wider inquiry must be held after the murder investigation.
St Conor's Primary School in Omagh reopened on Friday, four days after the house fire which claimed the lives of the family of seven.
Two of the children, Sean, 7, and Bellina, 4, were pupils at the school which is close to their home.
A prayer vigil was held as the seven bodies were removed from the fire-gutted house on Thursday.
The eldest of the five children, Caroline, 13, attended the nearby Sacred Heart College.
The two youngest were Clodagh, 19 months, and James, who was nine months old.