SHERIDAN — Investigators suspect arson may be the cause of an early morning fire Wednesday morning at the Sheridan County Attorney’s Office on Brooks Street.

Sheridan Fire-Rescue Chief Terry Lenhart said a sample has been sent to a laboratory to confirm whether a petroleum product, like gasoline, was used to start the blaze.

Lenhart said his crews were called to the scene at approximately 4:30 a.m. and saw flames inside the building and on an exterior wall.

“There was active fire coming from the north side of the building when we showed up,” he said, referring to the side of the building that faces the Farmers Insurance Group building. “There were flames coming out the first-floor window, and they extended up the siding on the exterior of the north side.”

Lenhart explained that a band of more than 30 firefighters from both SFR and Goose Valley Fire Department were able to accomplish initial suppression of the flames within six or seven minutes of their arrival.

Crews first attacked the fire with water hoses externally and then entered the building to finish the job.

From there, firefighters stayed on the scene for hours afterward for overhaul and mop-up operations.

“You have to keep looking for any little hidden, remaining fires, like in the cracks of the wall or places like that,” he explained.

“We had a great response with all cooperative agencies,” he said, adding that Rocky Mountain Ambulance and the Sheridan Police Department also helped with the logistics of the structure fire.

Lenhart said the exact location of where the fire began has not yet been determined.

The lower level of the building consists of a roaming office space surrounding a staircase with hallways near the back of the building. The building was initially constructed in 1910 and had extensive restoration work done in the spirit of historical accuracy.

Lenhart said the majority of the fire was on the interior of the first floor of the building. He estimated approximately 25 percent of that level of the building was damaged by flames, while the rest of the first floor was affected by heavy heat and smoke damage. The upper and lower levels were less severely affected, but were also scarred by smoke and heat.

The incident remains under investigation and Sheridan Police Department representatives have said they plan to bring in the authorities from the Bureau of Alcohol, Tobacco, Firearms and Explosives to assist.