Emergency services were alerted to a fire at Tullis Russell Paper Mill complex in Glenrothes at around 3.40am.
Upon arrival, police and fire services established that there were in fact a number of incidents ongoing.
Initially eight units of Fife Fire and Rescue Service attended the scene – at one stage over 50 fire fighters were involved.
Detective Sergeant Graeme Dursley said: “It’s too early to speculate on the cause of the fires at this time, however as there are a number of seats of fire the incident is being treated as suspicious.
“Fire officers are still currently working within the area and a joint enquiry with Fife Constabulary will be carried out to ascertain the cause.”
DS Dursely also appealled to anyone who has information about the incident or saw anyone in the vicinity of the complex between 2am and 4am to contact Fife Police on 0845 600 5702, or Crimestoppers on 0800 555 111, where all calls will be treated anonymously.
The fires have now been brought under control and there have been no casualties.