The fire that destroyed the old high school in Big Timber was caused by humans, but authorities did not say how the fire started.
The state fire marshal released the finding Thursday, just less than a week after the fire broke out.
A press release from the Sweet Grass County Sheriff's Office states the fire's point of origin was found, but no accelerants or evidence of accelerants were found at the scene.
In the days following the fire a portion of the building was demolished so authorities could safely enter the building and conduct an investigation.
The owner of the building couldn't be reached, so a search warrant was obtained to complete the investigation.