Investigators know where the deadly April 1 fire started at a Spearfish home but they are having trouble pinpointing the exact cause.

According to a release from Lt. Boyd Dean of the Spearfish Police Department, they believe the fire started on a porch where there was a 20-gallon metal trash receptacle used for ash and hot coals from a wood burning fireplace. This is also an area where cigarette smoking materials were disposed of by occupants of one of the living unit (it was a multi-family home).

With two separate possible ignition sources, investigators can’t determine the exact cause. They did rule out electrical since there was no wiring or appliances in the area where the fire started.

Five children died in the fire; all of them found in an upstairs bedroom.