Gardaí in Milford were on route to a call on Saturday afternoon last at approximately 3.15pm when they noticed smoke coming from a derelict house on Church Road.
They then discovered that a mattress had been set alight upstairs in the house.
The fire services attended the scene and extinguished the fire.
Gardai are urging anyone who may have been in that area with a dash-cam between 2pm and 3.15pm to make the footage available to them at Milford Garda Station at 074-9153060.
