Justin Sholly, 29, was arrested and faces several felony arson charges on Tuesday.
He was a member of the Perseverance Volunteer Fire Company, according to officials.
Investigators say he allegedly set three fires in Souderton and Franconia Township late last month, all within about 24 hours.
In each case, investigators say Sholly would then respond with his fire company to put them out.
Two barns and several vehicles were damaged.
Police say license plate readers helped them identify Sholly as the suspect.
They also say he allegedly admitted to the arsons after being confronted.
He allegedly used fire starter logs, which were found in his vehicle.
"Certainly never thought he was capable of doing something like that," said Nick Clemmer, who lives near a storage barn that burned early Friday morning, and called 911.
Clemmmer knew Sholly and never thought he would do something like this.
"He worked at the boys and girls clubs where my kids went when they were younger," Clemmer continued.
In total, 18 civilians were put into harms way, and had to be evacuated because of the fires. No one was injured.