A derelict industrial site in Desborough has been attacked by arsonists for the second time in the last eight weeks.
Firefighters tackled the blaze at the old Lawrence Factory on Harborough Road after the alarm was raised at 1.45pm on Saturday afternoon.
The offenders set alight a pile of rubbish on the first floor of the building – and flames quickly spread to the interior.
Fire crews from Desborough and Kettering raced to fight the fire.
The incident has been referred to the Arson Task Force.
The special unit brings together the police and fire service in Northamptonshire as it sets out to combat arson attacks.