Three cars and a tree were set alight in random deliberate acts of arson across Canberra's inner north, police say.
Firefighters and police were called to separate car fires in Braddon, Reid and Ainslie between 9.30pm and 10.30pm on May 28.
Police believe the fires are all related, but said they had no reason to believe the cars or the homes were targeted for any specific reason.
The first incident happened about 9.30pm when a tree was set on fire near the intersection of Drake Street and Higgins Crescent in Ainslie.
This was followed by a silver Volkswagen getting torched about 9.45pm in Doonkuna Street, Braddon.
A second silver Volkswagen was set on fire on Amaroo Street, Reid near St John's Church at 10pm.
The cars had not been reported stolen, police say.
Finally, about 10.25pm a silver Ford Focus was set alight on Constitution Avenue, Reid near CIT.
Acting ACT Fire & Rescue Superintendent Jim Walsh said one home had to be evacuated due to smoke.
"We needed to clear that with atmospheric monitoring to ensure that the environment was safe for the people to reoccupy their house, which they did," he said.
All the cars were written off by fire damage, Superintendent Walsh said.
Four out of the ACT's 10 fire trucks were sent out to the fires, with crews from the Ainslie, Fyshwick and Aranda stations attending the blazes.
Witnesses reported seeing a person on a motorbike leaving each of the incident scenes.
When asked if the car fires were part of broader increase in arson, Superintendent Walsh said they're seeing peaks and troughs.
"We got a little bit of a peak at the moment, but that could be all quiet again by next week," he said.
Anyone who witnessed the fires or has information is asked to contact police.
