SALEM, Ore. (AP) — Two people, a cat and dog were found dead Monday inside a fifth wheel travel travel trailer east of Salem after suspected carbon monoxide poisoning, according to the Marion County Sheriff’s Office.

Someone called authorities on Monday morning saying they had gone to check on the father and daughter after not hearing from them since Saturday and found them not breathing inside the trailer, the sheriff’s office said in a news release Tuesday.

Detectives believe the deaths were the result of carbon monoxide poisoning from a propane heater being used inside the trailer.

The sheriff’s office identified the people who died as 50-year-old Richard Yaple of Salem and his 17-year-old daughter Hannah Yaple of Keizer.