Police in Swanage are searching for vandals after a spate of graffiti and damaged cars.
Bus shelters, a railway bridge and buildings were defaced - while police are investigating whether this is linked to a number of damaged cars.
A 17-year-old boy has been arrested and is helping officers with their enquiries.
Deputy Neighbourhood Inspector Jon McCarthy said: "We are disgusted that someone, or a group of people, have felt it necessary to deface the lovely seaside town of Swanage.
"It creates a bad image for the town and will probably cost the council thousands of pounds and many hours of hard work to remove.
"We are asking anyone who may know who has done this, or recognises the 'tags' to please let us know so we can stop this from happening again.
"There were also many cars vandalised on the same evening. If your car was damaged please report this to Dorset Police. We can't act upon incidents we don't know have happened."
Witnesses or anyone with information should contact Dorset Police on 101, quoting incident number 31:140.