Fire crews were called to three arson attacks in the same area of Peterborough within two hours on Saturday night.
Crews from Dogsthorpe and Stanground were first called to a small fire in a derelict building in Padholme Road East at 5.52pm on Saturday April 8.
Firefighters wearing breathing apparatus used a hose reel jet to extinguish the fire and returned to their stations by 6.40pm.
But, at 6.40pm crews from Stanground and Whittlesey were called to conifers on fire in close proximity to a house in Saxon Road.
Firefighters used two hose reels to extinguish the fire and returned to their stations by 7.59pm.
And at 7.58pm a crew from Stanground was again called to a fire in the open in Padholme Road East where a mattress was set alight.
Firefighters used a hose reel to extinguish the fire and returned to their stations by 8.49pm.
All three incidents were arson attacks.
Anyone with information should contact police on 101 or call Crimestoppers anonymously on 0800 555 111.