Police made a total of six arrests in the hours immediately following the suspected arson attack on the family home of 35-year-old Michelle Pearson and her children in Jackson Street, Walkden, at around 5am. Two 16-year-old boys were also in the house when the blaze broke out but managed to escape before fire crews arrived.
GMP's Territorial Commander for Salford, Chief Superintendent Wayne Miller, said: "I can not imagine what their family are going through, they are obviously completely devastated, the loss of a child in any circumstances is unthinkable; to lose three in such deplorable circumstances, words can not describe".
Ch Supt Wayne Miller said Greater Manchester police were treating the incident as a targeted attack after recovering CCTV from the area.
Although seven people were believed to have been trapped in the family home along Jackson Street, four children died. Formal ID has yet to take place.
Ms Pearson, 35, remains heavily sedated in hospital while a three-year-old child remains in a critical condition today.
Children at Harrop Fold High in Little Hulton, where Demi was a pupil, and Bridgewater Primary, where Lacie and Brandon attended, are being given counselling and support from staff.
Lacie Pearson, seven, lost her life in the blaze Demi Pearson, 14, also died in the fire Lia Pearson, aged just three years old, has died in the hospital.
It is understood Demi was pronounced dead at the scene, but Brandon and Lacie died in hospital.
Very sad news, 3-year-old Lia Pearson has sadly died in hospital after fire in her home in Salford.
They are accused of throwing three petrol bombs into the house, in Walkden, as Michelle Pearson slept with her children. She has passed away peacefully.
Zac Bolland, 23, of Blackleach Drive, Walkden, and Courtney Brierley, 20, of Worsley Avenue, Walkden, have also been charged with murder and will appear alongside Worrell on Friday.
Bolland and Brierley both remain in custody and are due to appear at Manchester and Salford Magistrates' Court later (Wednesday 13 December 2017).
The IPCC investigation is under way and is expected to focus on the contact between Greater Manchester Police (GMP) and the family after officers were called to the address in the hours before the fire.