Police investigating a fire at the former Derbyshire Building Society headquarters in Duffield have made a further appeal for information.
The fire was discovered at about 7pm on Tuesday June 24 in an insecure disused building. There was no power to the building - so officers are treating the fire as suspicious.
The A6 was closed until 8.15pm while fire-fighters tackled the fire.
Police are appealing to anyone who saw anything suspicious in the area or anyone running away from the site to contact PC Daniel Newcombe on 101.