Last Sunday evening there was a fire inside a preschool yard at Hammarens preschool in Södra Sunderbyn.
After an intervention by people nearby, the fire was extinguished before it caused any major damage.
The incident has been reported to the police and last week a fire was stopped next to Svedjeskolan in the district of Hertsön.
- We have requested increased surveillance by our security company in connection with the start of school week.
So far, the fires that have been discovered have been put out, I don't dare think about what could have happened if passers-by with civil courage had not raised the alarm and intervened when they discovered the fires, says Annicka Backman, operations manager of the preschool, to Luleå municipality's website.