Thames Valley Police is appealing for witnesses to an arson in Slough.
The incident occurred around 3pm on Saturday 12 November near to Lismore Park.
The occupant of the house smelt burning and located a fire inside their front door. When attempting to put the fire out, a member of the public assisted.
Investigating officer Detective Constable Rae Fitzell, based at Reading police station, said: “We are looking to speak to the member of public who kindly helped put this fire out and anyone else who was in Lismore park area at the time.
“Please get in touch by either making a report online or by calling 101, quoting reference number 43220512115.
“Alternatively, for 100% anonymity, you can also call the independent charity Crimestoppers on 0800 555 111.”