HARMONY GROVE - Investigators for the California Department of Forestry and Fire Protection are investigating three early morning fires that have occurred since June 23 along Harmony Grove Road, authorities said on Tuesday.

Each fire was reported between 1 and 3 a.m., and none has caused any injuries or structural damage, said Battalion Chief Jim Garrett, of the state firefighting department.

"They're under investigation," Garrett said. "They could turn out to be suspicious or they could be a coincidence."

The fires burned a 150-foot by 150-foot spot on June 23 in an area near Harmony Grove and Elfin Forest roads, a 10-foot by 10-foot spot on July 6 in the same area, and a 100- foot by 100-foot spot on July 14 near Harmony Grove and Questhaven roads.

Any suspicious activity should be reported to the Sheriff's Department and Fire Department, said Don Heiser, deputy fire chief of the Elfin Forest/Harmony Grove Fire Department.

"If you see someone throw a lit object or speed away, a license plate number or vehicle description can be really good stuff," Heiser said.