Police have charged a father and his two sons with murder following the fatal flat fire in Langley Mill.
Peter Eyre, 43, and Anthony Eyre, 21, of Central Avenue, Sandiacre, and Simon Eyre, 24, of New Tythe Street, Long Eaton, have each been charged with three counts of murder.
They are due before magistrates in Chesterfield on Friday morning.
A 17-year-old, also arrested on suspicion of murder, has been released on bail. He is from Long Eaton.
Amy Smith, 17, her six-and-a-half-month-old daughter Ruby-Grace Gaunt and friend Edward Green, 17, from Belper, all died when a fire broke out at Amy’s flat in North Street.
Police can now reveal that all three died of smoke inhalation.
The fire happened at about 4am on Sunday. An 18-year-old and 17-year-old man were rescued from the flat by neighbours.
Anyone with information should call police on 101 or Crimestoppers on 080 0555111.