Three men have been arrested on suspicion of murder following a house fire that killed three people in Derbyshire.
A 17-year-old, a 21-year-old and a 43-year-old were arrested late on Monday night, police said.
Amy Smith, 17, and her six-month-old daughter Ruby-Grace Gaunt died, along with Ed Green, also 17, at flats in Langley Mill on Sunday.
Police said they are still working to establish the cause of the fire.
The arrested men, who are from Sandiacre and Long Eaton, remain in custody.
Police were called to flats in North Street at 04:00 BST following reports of a fire.
Two men, aged 18 and 17, who were also inside the premises at the time, were rescued by neighbours and treated for smoke inhalation.
Assistant Chief Constable Martyn Bates, of Derbyshire Police, said: “The cause of the fire is still unknown and the possibility that it was started deliberately is just one of many lines of inquiry we are pursuing at this time.”
He urged anyone with information to contact police.