BILLINGS, Mont. (AP) — Montana authorities say two men arrested in a mobile home blaze that killed four people lit an apron on fire during a party and then left.

Court documents filed Friday by Yellowstone County prosecutors say the two men thought the fire was out, and later panicked when they returned and saw the residence aflame.

Preliminary autopsy results show the victims died of smoke inhalation.

Suspects Zaccary John Kern and Robert Eric Bottenhagen, both 21 and from Billings, are being held at the Yellowstone County Jail.

They each face four counts of negligent homicide and one count of felony arson stemming from the Thursday blaze.