Police investigating a fire at a house in North Wingfield in which four people died do not believe it to be suspicious at this stage.
Emergency services were called to the blaze on Williamthorpe Road at around 5am on Wednesday.
Claire James, 27, Josie Leighton, 32, and her two sons Tyler Green, nine, and Jordan Green, 12, died following the fire.
Post mortem examinations carried out today revealed all four died from smoke inhalation.
Investigations into the exact cause of the fire are continuing.