Officers investigating the flat fire in Langley Mill in which three people died are to spend the next two days in the community appealing for witnesses.
Although people have come forward since the blaze, which happened at about 4am on Sunday, June 21, police believe there could be other residents who are yet to make contact.
The mobile police station will be at several locations across the town today and tomorrow and officers will be handing out appeal leaflets and posters, asking anyone who was in the area between 3am and 4am that day to come forward.
Amy Smith, 17, and her six-and-a-half-month-old daughter Ruby-Grace Gaunt, who lived in the flat, died in the fire along with friend Edward Green, 17, from Belper.
A man and his two sons have been charged in connection with the fire. 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.
Assistant Chief Constable Martyn Bates, of Derbyshire police, said: “There could be people out there who saw something suspicious that night but who haven’t come forward because they think what they saw is insignificant.
“I would urge them to get in touch because their information could be important to the officers who are trying to build a bigger picture of exactly what happened.”
Anyone with information should call police on 101 or Crimestoppers on 0800 555 111.