Police are trying to catch an arsonist who has been targeting For Sale signs.
A total of nine signs have been torched over the past two weeks in the Headington area of Oxford.
The first incident was outside a home in London Road at 0422 GMT on 13 March. The most recent attack was on Saturday in Merewood Avenue in Sandhills.
Police said the arsonist's motive was unclear but appealed for witnesses in the London Road area where seven of the nine signs were destroyed.
A sign was also set alight in Delbush Avenue overnight between 21 and 22 March.
Pc Zoe Eele, from Thames Valley Police, said: "Most of these fires have been started along the London Road, which is a busy road at all times of the day with traffic coming in and out of the city, and I believe someone must have seen something.
"Other than destroying the signs, the fires haven't caused too much damage and we are keen to catch the person responsible before it potentially escalates and someone gets hurt."