The investigation continued Friday in a series of arsons in Gorham, with authorities working with evidence gathered from the fire scenes and following up on leads provided by the public.

“As far as our folks are concerned, we’ll be working through the weekend,” said acting state Fire Marshal Joseph Thomas.

Authorities have been asking for the public’s help in the case. Door-to-door distribution of fliers by the Gorham police and fire departments has generated calls.

Residents are being asked to be aware of anything out of the ordinary in their neighborhoods — whether it’s an unknown vehicle, an unfamiliar person walking through the neighborhood or someone acting suspiciously, Thomas said. It will take time to develop substantive leads out of such tips, he said.

Sgt. Joel Davis of the Fire Marshal’s Office said investigators have conducted 50 or more interviews in recent days.

“The majority of the time, these cases are interview-driven,” he said.

Davis estimated that authorities passed out 600 to 700 fliers while canvassing the western and northern parts of town Thursday. That effort has drawn additional information from the public, he said.

So far, there are no suspects. There isn’t enough information to establish a viable profile of an individual. “It’s wide open,” Thomas said.

He would not say whether any evidence that could yield DNA or fingerprints has been collected.

The string of fires started March 27; the most recent one broke out Wednesday night. No obvious pattern has emerged.

The first fire was at a home on Spiller Road, late in the morning on a Tuesday. The SnoGoers clubhouse on Mighty Street was leveled by the second fire in the early morning on a Saturday. A home being renovated on Great Falls Road was destroyed by a fire that broke out the next morning. A garage on Buck Street was destroyed a week later, in the afternoon. And the most recent fire — which caused minor damage to an unoccupied house on Dingley Spring Road – was set Wednesday night.

Gorham Police Chief Ronald Shepard, Fire Chief Robert Lefebvre and Thomas released a public safety announcement encouraging residents to come forward with information. They were asked to call police at 839-5581 or send email to dthompson@gorham.me.us.

“The investigating agencies appreciate your understanding and assistance during this critical investigation. We urge you to be familiar with your surroundings and watchful for suspicious activity,” the letter said.

Other agencies have offered assistance. The Maine Forest Service is making a helicopter available, and Thomas said it could be used at some point if investigators determine that an aerial view of the area would be valuable.

The federal Bureau of Alcohol, Tobacco, Firearms and Explosives has provided several agents and has contacted its profiler, said Dale Armstrong, the resident agent in charge in Maine.