State Police say an autopsy confirmed that carbon monoxide poisoning killed a 12-year-old girl during a pool-party sleepover at a Morgantown home.

Investigators have said a faulty heater for an indoor pool caused the odorless gas to fill the house on August 12. Cheyenne Hise was killed and five other children and a woman were sickened.

State Police say Hise and another 12-year-old girl were sharing a bed closest to the room containing the heater.

Hise was a student at Westwood Middle School.