Following post mortem examinations on the seven victims of the Omagh fire, it has been established that all died of smoke inhalation.
Arthur McElhill, Lorraine McGovern and their five children died in a house fire in Lammy Crescent last Tuesday.
The PSNI has insisted it is investigating seven murders and has denied reports that its inquiry was concentrating on one main suspect.
The house remains sealed off as the police continue to consider it a crime scene - a significant quantity of petrol was discovered inside the house.
An expert fire investigator from England has been called in in order to establish the origins of the blaze.
The end-of-terrace house in Omagh, Co Tyrone, was left a blackened shell and the roof destroyed during the fierce fire.
