COLUMBUS, Ind. — After nearly two weeks of combing through debris, investigators in Columbus said they’re unable to determine the cause of a fire that led to the collapse of a downtown building.

The Dec. 3 fire broke out around 11:50 p.m. at 422 5th Street. Crews responding to the scene saw flames and said part of the building collapsed while they were deploying hand lines near the back portion. Units from additional jurisdictions were called to help with the firefighting effort.

It took about four hours for crews to get the fire under control.

The building housed more than a dozen businesses; electricity had to be cut off to parts of downtown Columbus and a portion of 5th Street closed because debris was blocking the road.

While investigators believe the fire originated in a ground level storage building attached to the back of 422 5th Street and 440 5th Street, they couldn’t pinpoint an exact cause. Investigators from the Columbus Fire Department and Indiana State Fire Marshal’s Office combed through debris for several days.

As a result, the official ruling on the cause was “undetermined.”

“The fire will remain undetermined due to the fact that the building is too unsafe to conduct further investigation as is outlined under the National Fire Protection Association (NFPA) Standards,” said Columbus Fire Department Investigator Troy Todd.

“Undetermined” is one of four classifications employed by fire investigators. It’s used in cases in which they lack physical evidence or accounts of factors that caused a fire. The other classifications are natural, incendiary and accidental.