Three more suspicious fires burned in Santa Rosa on Wednesday, adding to a string of recent small blazes cropping up in town.
That brings a recent total of suspicious fires to at least 13 since the weekend.
Santa Rosa police and fire investigators are working together on the case, officials said Thursday.
The fires primarily are burning in dumpsters and garbage cans, often behind businesses and at apartment complexes.
They haven't caused serious damage or injury, but fire officials have said they fear the potential for a major fire.
Wednesday's fires occurred on Hampton Way, West Avenue and Stony Point Road at Glenbrook Drive, said fire officials.
This recent string of small, suspicious fires follows a long-standing pattern of such fires in Santa Rosa.
In January, Santa Rosa firefighters responded to four on a Monday afternoon.
Last October there were at least 20 in a short time period and in last spring fire officials reported at least six in close succession in March.