A fire which killed a mother and her four daughters in Lancashire was started deliberately, police have said.
The girls' father was resuscitated and taken to hospital
The bodies of Caneze Riaz, 39, and her daughters Sayrah, 16, Sophia, 15, Alicia, 10, and three-year-old Hannah, were found in the early hours.
Police said the house in Tremellen Street, Accrington, had been locked up from the inside and flammable materials used. A murder inquiry is under way.
The girls' father, Mohammed Riaz, is in a critical condition in hospital.
He had to be resuscitated by a firefighter at the scene and is being treated in Wythenshawe Hospital's burns unit, where he is said to be in a critical condition.
Det Supt Mick Gradwell, leading the investigation, said officers were waiting to speak to Mr Riaz at his bedside.
The couple are said to also have a fifth child, 17-year-old Adam, who has been receiving hospital treatment for leukaemia.
At a press conference, police said there were several seats of fire which were started using flammable materials.
They are now appealing for anyone who saw anything suspicious in the area on Tuesday night to come forward.
Mr Gradwell said: "The house was secured and locked from the inside.
"Early indications are that whoever set the fire, and carried out some other suspicious activity I can't go into at this stage, did not leave the premises.
"However, I can't discount that a scene has been staged to suggest this."
The house has been sealed off while police forensic officers examine the scene. Post-mortem examinations of the bodies were taking place on Wednesday.
Mr Gradwell said: "It is a murder inquiry because the fire was set deliberately with accelerants used. This is a deliberate fire and there is no evidence that anybody left that house.
"The indications are at the moment it is contained within that family."
Mr Gradwell extended his deepest sympathies to the Riaz family and said officers were now working with relatives to build up a picture of them.
He revealed that all of the people who died in the fire were found in their beds.
Ch Supt David Mallaby, divisional commander for the Accrington area, said there was a deep sense of loss in the community.
"Rarely if ever have I come across a tragedy of this nature, particularly when one considers the extent to which it may well have been a deliberate event.
"The sense of loss, the sense of tragedy and the sense of disbelief is quite staggering."