Police in Fife are appealing for witnesses and urging people to avoid a building set alight in Dalgety Bay.
The incident took place at a disused premises in Hillend Industrial Estate and was reported around 6.40pm on Wednesday 6 September.
Local residents were advised to stay indoors as a precaution due to the presence of a small amount of asbetos within the building.
This was found to have been unaffected by the fire and there is no risk to the community.
The blaze was extinguished shortly after 10pm and traffic restrictions were removed around 6.40am on Thursday 7 September.
Following joint enquiries by the Scottish Fire & Rescue Service and Police Scotland, the fire is currently being treated as deliberate.
Sergeant Kenny Bow of Dalgety Bay said: "We'd urge anyone who may have seen suspicious behaviour in the area around this time to get in touch with us as soon as possible.
"The building is structurally unstable and is not safe to enter. We'd urge parents in particular to speak to their childen and reinforce the risks of entering the building and we ask local residents to be vigilant and report any signs of entry to us.
"Lastly, I want to take this opportunity to thank the community for their cooperation and continued support as we conduct enquiries within the area."
Anyone with information is asked to contact officers at Dalgety Bay Police Station via 101, quoting incident number 3038 of 6 September, or report this anonymously to Crimestoppers on 0800 555 111.