Rich Denison, Townsquare Media

Fire investigators say the Sheep Herder Hill fire on Casper Mountain was human-caused. The fire, which destroyed 37 homes and cabins on Casper Mountain and burned 15,500 acres started around 4:00 p.m. on Saturday, September 9th.

Officials say the exact cause is not yet known, but they believe the fire started on the west side of an ATV/Snowmobile trail, off of Circle Drive.

Although they believe the fire was intentionally set, they did not find any signs of incendiary devices. There were reports of motorcycles and four wheelers in the area prior to the fire, and investigators recovered small metal fragments consistent with exhaust particles from a gas engine.

They also could not rule out that the fire may have been sparked by a discarded cigarette. The investigation on the exact cause, and who might be responsible continues.

Initial estimates are that fighting the fire cost more than $3.3 million dollars, a figure that does not include the damage done to the homes and cabins.