Detectives have launched an arson investigation following a fire at a disused building in Runcorn.
Officers were alerted to the fire at Halton Law Courts on Second Avenue at around 8pm on Monday 13 December.
Cheshire Fire and Rescue Service (CFRS) attended to the scene and tackled the blaze for a number of hours.
The cause of the fire has been confirmed as being started deliberately from materials inside the premises.
Police are now appealing for information from members of the public and encouraging them to get in touch.
Detective Sergeant Alex Reeves, from Halton CID, said: “The fire is being treated as arson and our investigation is ongoing to identify who was responsible.
“After reviewing CCTV footage we believe the fire was already underway prior to emergency services attending to the scene and I’m asking members of the public to come forward if they saw any suspicious behaviour from around 7pm that evening.
“The investigation is in its early stages and I would ask people who have CCTV or dash cam footage that may be useful to get in touch.
“Thankfully there have been no reports of anyone sustaining any injuries however I want to remind the public of how dangerous and unsafe it can be to enter these types of buildings and to please keep away from them.”
Anyone who has information is asked to contact Cheshire Constabulary online quoting IML 1155347.
Information can also be provided anonymously by calling Crimestoppers on 0800 555 111.