Investigators who are trying to solve a string of arsons that has put Gorham residents on edge say there’s a good chance a local resident set the fires.

“We think it’s someone that must know that area” of north Gorham, said Sgt. Joel Davis of the state Fire Marshal’s Office. “We’ve got people looking at the different sites to try to work on the commonality to really try to figure that out.”

The first fire broke out at a vacant house on Spiller Road at 11 a.m. on Tuesday. Another fire was set at 1:30 a.m. Saturday at the Gorham SnoGoers clubhouse, at 209 Mighty St.

At 6:50 a.m. Sunday, fire destroyed the vacant house at 5 Great Fall Road.

“They were all similar,” Davis said.

And unfortunately, there are many vacant buildings in that section of town, he said.

The main concern with such fires is the risk of injury, when firefighters and police rush to the scene or when someone goes into a burning building, Davis said.

Gorham police and fire marshal’s investigators are interviewing people who arrived at the fires soon after they started, as well as people who have reported tips.

“It’s pretty much a witness-driven investigation at this point,” Davis said.

Investigators have sought help from the Maine Forest Service because of its expertise in finding evidence of fire-setting in woodlands, Davis said. The federal Bureau of Alcohol, Tobacco, Firearms and Explosives also has been consulted.

Firefighters have been trained to look for evidence that might be important to the investigation and, if possible, preserve it, Davis said. “That’s a hat or piece of clothing, cigarette butts … tire tracks.”

Firefighters often help solve cases by noting any cars they see leaving a fire scene as they respond, he said.

The fires are disturbing for firefighters and the public, said Gorham Fire Chief Robert Lefebvre.

“It does make people nervous, the general public, because at least right now, we don’t have an idea” who is setting them, he said. “You don’t know whether they’ll try again. Sometimes they will. Sometimes they won’t.”

Vacant building can be magnets for arson because people can set fires without being seen. The buildings also can also attract homeless people and mischievous youths.

One of the first groups of suspects investigators look at are people who have shown similar behavior and are not in custody, Lefebvre said.

Staff Writer David Hench can be contacted at 791-6327 or at: dhench@pressherald.com

Correction: This story was revised at 1:01 p.m., April 4, 2012, to correct the date of the fire on Spiller Road. The fire at a vacant house broke out at 11 a.m. Tuesday. March 27.