No criminal activity is suspected in a fire that badly damaged a house in Butler early Monday morning, fire officials said.

“The cause is undetermined but it does not appear suspicious at this time,” Trooper Luke Nelson, a deputy fire marshal, said Tuesday after investigating the scene of the blaze at 219 E. Brady St.

“There’s nothing immediately consistent with an intentionally set fire.”

Investigators said the fire started shortly after 2:30 a.m. in the roof area of the three-story house that includes a finished attic.

Flames were spotted on the upper floors in back of the home when city firefighters got there.

“We made an interior attack and contained the fire to the rear second and third floors,” said Butler Fire Chief Nick Ban. “We had it contained in 45 minutes to an hour. It was pretty stubborn because it got into the roof.”

Heat from the fire also melted the vinyl siding of another home next to the house.

No one was injured and damage to the house that caught fire was estimated at $40,000. Owner Thomas Rodgers of Butler only bought the property last week.

The blaze initially raised suspicion because the home had not been occupied for about a year and because there were no utilities connected to the house.

The utilities were disconnected in September, Ban said.

Rodgers on Thursday purchased the house for $21,000 through an online auction, authorities said.

“He bought it as a rental property,” Ban said. Officials noted the house appeared to be divided into two or three apartments.

The house was not insured.

“He was in the process of getting (insurance) set up,” Nelson said of Rodgers.

Investigators said there was no evidence of a recent break-in at the house, which had no furniture or other contents.

“There was nothing to steal in the property,” Ban said.

Months ago, Butler police said, the house was burglarized and some of the copper pipes stolen.

Nelson said his investigation found no signs that squatters had been in the house or that the home recently had been vandalized.

While a cause of the fire is unknown, one theory emerged Tuesday, investigators said.

“Neighbors reported some fireworks were being set off in the area over the weekend,” Ban said.

“Maybe an errant firework got into the gutter and ignited leaves (in the gutter).”

Nelson did not rule out that scenario either.

“It looked like the fire started in the eaves of the roof,” he said, “and the gutters were packed with debris, leaves, branches and stuff.”

The house is “repairable,” Nelson said, but renovating it would not be cheap.

The Butler Eagle could not reach Rodgers for comment.