KENNEBUNK — At least one of the dozen or so wildfires that spread through southern Maine on Patriots Day weekend has been deemed “suspicious” and is the subject of an ongoing investigation.

The fire burned through several acres of hardwood forest off Maguire Road in Kennebunk and threatened several homes on Saturday afternoon.

Local fire departments and the Maine Forest Service began responding around 3 p.m. and had the fire contained by around 6 p.m.

Unlike the other brushfires around the state over the weekend, no cause could be easily found for the Kennebunk fire, said Ranger Claudette Desautels of the Maine Forest Service.

Desautels said investigators did not find anything that would make them think the fire was suspicious. But the determination was made because investigators ruled out some of the usual causes of brush fires — burning debris, cigarettes, campfires, lightning and railroad traffic.

Fire danger has been “very high” in the state this month because of dry and warm weather, Desautels said, helping to create perfect conditions for wildfires.

In other fires over the weekend, most of the possible causes were found quickly, she said. But the Kennebunk fire was in an area about 100 yards from any home, with no trails, no ATV traffic, and no sign of human use.

“We’re calling it suspicious and incendiary, and our investigation is ongoing,” she said. “But we may never know what caused it.”

Two other troublesome brushfires occurred Sunday.

On Lasalle Island off Rockport, a Forest Service helicopter carried firefighters and equipment from the mainland and dropped water onto a fire.

In the Unorganized Territory near Medway, a wildfire burned at least 32 acres of grass, brush and timber.

Forest Service Ranger Jeffrey Currier said other fires were reported in the southern half of the state, including in Manchester, Winslow, Whitefield, Fairfield and some in the Penobscot County area.

Currier said most of those fires were put out relatively quickly by the Forest Service and local fire crews.

– The Associated Press contributed to this report.

Staff Writer Ray Routhier can be contacted at 791-6454 or at: [email protected]