GRAND FORKS, N.D. (AP) — Investigators say a fatal weekend fire in Grand Forks was the result of an accident. Fire Marshal Rod Freitag said Tuesday it was caused by improper handling of smoking materials.

Officials say a smoldering cigarette ignited combustible materials next to a bed. And, the burning materials ignited the mattress. The fire early Saturday killed 40-year-old Sarah Gatica.

Firefighters rescued a second resident who was taken to Altru hospital. The bedroom sustained moderate damage. Fire officials say there was smoke and heat damage throughout the main floor.