Firefighters say a total of 13 fires were set Saturday night within two hours of each other.
RELATED: Multiple grass fires extinguished in Santa Rosa
There were three next to the railroad tracks along Hearn Avenue and 10 along the Santa Rosa Creek Trail.
It is especially distressing to residents who are still traumatized from the deadly wildfires that swept through here in October. They say it is cruel for someone to do this.
Santa Rosa resident Alexis Bloom says, "It's pretty distressing. If anybody is familiar with the community, they would know that it is disrespectful."
Firefighters say they understand.
"We know the community has been through a lot. We know the community is on edge and that's why we are taking this so seriously to figure out who this is and to put it to a stop," said Assistant Fire Marshal Paul Lowenthal.
Firefighters say they respond differently since the October fires. They now call other agencies sooner and ask for help.
They believe that the suspect used some sort of lighter and is likely getting around by bicycle. Residents say it is just cruel to do this here.
The reward is being offered by the Sonoma County Alliance "Take Back Our Community Program." Police say no one was hurt in the fires and no structures were damaged.
Santa Rosa officials are asking for the public’s help as they look for the person who set 13 fires Saturday night in 2 hours. pic.twitter.com/zpvXOxdY42— Amy Hollyfield (@amyhollyfield) June 18, 2018