A woman found dead in August inside her mobile home in the Queensgate area died of natural causes, according to the Benton County coroner.
Rikki L. Beaulieu, 56, was found Aug. 1 inside her Crestwood Drive home when Richland police were asked to check on her.
The circumstances were unusual enough to prompt the coroner and police to investigate further.
The results of the lab tests returned recently and they showed Beaulieu died from a heart attack, said Benton County Coroner Bill Leach.
Leach used a private lab for the testing because of a months-long statewide backlog at the Washington State Patrol crime lab.
Richland police Sgt. Drew Florence said they do not believe any foul play was involved, but the investigation has been forwarded to prosecutors to review as a matter of procedure.