Pittsboro, N.C. — Crews are using cranes to remove debris from the remains of the burned-out Chatham County Courthouse.

The 129-year-old landmark in Pittsboro was ravaged by a fire late Thursday afternoon. Early Friday, the courthouse's clock tower collapsed, and firefighters spent the day putting out hot spots.

Chatham County spokeswoman Debra Henzey said that crews will focus on removing large pieces of debris and putting out any remaining hot spots. The goal is to make the structure safe for workers to enter and begin to investigate and further assess damage.

Getting into the building's remains is key to finding out what caused the fire, which at this point, appears to have been accidental and started in the attic, according to officials. The State Bureau of Investigation, U.S. Bureau of Alcohol, Tobacco and Firearms and Chatham County fire officials are investigating.

“We have made good progress with interviewing people and reviewing photos, including overhead shots from helicopters," Chatham County Fire Marshal Thomas Bender said. "But we can’t complete our investigation until we get into the courthouse."

Damage doesn't appear to be as bad as officials initially feared, County Manager Charlie Horne said Friday. An initial exterior evaluation by structural engineers indicated that the walls, except for the gables, might be salvageable.

"It was built to last when it was built," Horne said.

The ceiling is intact above a room occupied by the Chatham County Historical Association, raising hopes that historical artifacts and documents, including some from the colonial era, might be saved.

The traffic circle around the courthouse will be closed for at least the next few days, officials said. Traffic is being detoured.