MOUNT CARMEL — A fire that destroyed state Rep. Robert Belfanti’s office early Sunday morning was deliberately set, a state police fire marshal said.

Mount Carmel police officers on patrol around 1 a.m. noticed a window pane on the front door to the office, at 15 West Ave., was broken, according to Belfanti, D-107, of Mount Carmel. When they investigated, they discovered the building was on fire.

Firefighters from several area companies converged on the scene, the representative said. “The entire block was back-to-back fire trucks.”

Jack Williams, assistant chief of the Mount Carmel Fire Department, said it took firefighters about 15 minutes to get the blaze under control. They were able to keep it from spreading not only to the second floor of the building, but also to neighboring structures, despite their close proximity, he said.

The building is owned by John Martin Quinn, 55, Kulpmont, according to Fire Marshal Norm Fedder. Belfanti’s office occupies the entire first floor, while Timothy Ray Rosancrans rents out the second floor.

The fire caused an estimated $150,000 in damage. Quinn is insured, according to state police.

Fedder said there were four separate fires started in the office and all accidental causes were eliminated.

However, Belfanti said he went through the building later and believes there may have been more than four individual fires.

He said someone had stacked papers — either from filing cabinets or brochures — throughout the office and set them on fire. One stack was placed under a wall-mounted propane heater, he said. “It melted the bottom, but at least it didn’t explode.”

Several pieces of furniture and memorabilia owned by Belfanti were destroyed, as well as office supplies owned by the state including computers, copiers and fax machines. Those items are insured by the state, he said, and he believes his homeowner’s insurance might cover the personal items he lost.

The representative said he’s not sure whether any important documents were lost in the fire.

“The filing cabinets look to be intact. I don’t know if water got to them,” he said. “I didn’t want to disturb anything while (the police) are doing their investigation.”

Belfanti said he was at home, only two blocks away from the office, when one of his staffers knocked on the door and told him the building was on fire.

“I’m just sick over it,” he said Sunday afternoon, after a long, virtually sleepless night. “It would be different if it was something electrical in the basement or something like that.”

He said he gave police the names of two “disgruntled” people who had called his office in the last couple weeks.