Humberside Police is investigating three more barn fires in the Pocklington and Market Weighton areas.
Police were called during the early hours of Wednesday 06 March in connection with three separate incidents in which barns and hay had been set alight.
The first incident was reported to police at 2:34am. A barn had been set alight on Pocklington Lane in Burnby, causing a significant amount of damage to the barn and hay inside, say officers.
Humberside police also say that at 4:44am police were called after a large quantities of hay bales had been set alight on a farm in High Catton.
They also report that there was a further incident on Lock Lane, Holme on Spalding Moor, where machinery and hay bales were damaged after a fire was started inside a barn.
Police are also looking into a 4th fire involving some hay bales in Old Goole.
Investigations into all of these incidents are in the very early stages say Humberside Police and at this time officers are still working to establish if they are connected.
Anyone with information can call police on 101 quoting log 56 of 06 March 2013.