Five people are being questioned over the suspected murder of three children who died in a house fire in Salford.
A 14-year-old girl, named locally as Demi Pearson, died at the scene of the blaze which broke out in Jackson Street, Walkden, at about 05:00 GMT on Monday morning.
An eight-year-old boy and a girl aged seven died in hospital, while a three-year-old is in a critical condition.
Their mother, named as Michelle Pearson, 35, is in a serious condition.
Ms Pearson has been heavily sedated and has not yet been told her children are dead, a Greater Manchester Police (GMP) spokesperson said.
One other person was taken to hospital, while two 16-year-old boys who were also in the house freed themselves before fire crews arrived.
Police confirmed they had been in contact with the family very recently and had visited the house in the hours before the blaze.
The case has been referred to the Independent Police Complaints Commission (IPCC).
Detectives are questioning three men, aged 18, 20 and 23, and a 20-year-old woman on suspicion of murder.
A 24-year-old man is being held on suspicion of assisting an offender.
Demi Pearson was a pupil at Harrop Fold School in Salford, which featured in the Channel 4 documentary Educating Greater Manchester.
Head teacher Drew Povey said: “We are devastated at the tragic loss of life today in our community. Our thoughts and prayers are with the family involved.”
Ch Supt Wayne Miller said police were appealing for witnesses or those with information about the events leading up to the fire.
“In what is such a heartbreaking set of circumstances, we have been doing our very best to support the family in every way that we can and carry out our inquiries quickly and sensitively,” he said.
Damian O’Rourke from Greater Manchester Fire and Rescue Service said: “Firefighters arrived within minutes and were faced with a very serious and well-developed fire involving the ground and first floor.
“Knowing there were people trapped inside, firefighters wearing breathing apparatus immediately went in and quickly rescued five people from the house but sadly three of those people died.
“Our first thoughts are with the family and friends of those involved.”