PETROL was thrown on to the steps of a house, then set alight.
Police are now investigating the arson attack which happened in the garden of a house at Mill Street West in Dewsbury between 8.30pm and 8.45pm on Saturday.
Detectives believe petrol was thrown on to the steps of the house before being lit and causing damage.
No-one was injured during the fire.
Scenes of crime officers have attended the address to carry out forensic inquiries and detectives have been viewing CCTV from the area.
Police are looking for a man of medium build, between 5ft 2ins to 5ft 4ins tall, with a round figure.
He has shoulder-length dark hair and was wearing light coloured trousers.
Anyone with information about the incident is asked to contact Dewsbury CID on 01924 431022.