Oak Grove, MO – The carbon monoxide poisoning death of two people in Oak Grove in August has been classified as an accident, according to Oak Grove police.

Joyce M. Bentley, 62, and Megan Wyatt, 17, died at Bentley’s apartment Aug. 16 on the 100 block of Dogwood Street.

Robin Ferguson, 16, was treated for carbon monoxide inhalation. She has been released from the hospital but her long-term ramifications, if any, are unknown.

Bentley, who was Wyatt’s grandmother, pulled into the driveway. She let the girls out of the car, according to Oak Grove Police Chief Bob Muenz.

The girls went upstairs to play. Bentley drove the car into the single vehicle garage, Muenz said.

“Grandma parked the car and came into the house,” Muenz said. “They all went to bed and unfortunately two of them never really woke up.”

The investigation revealed and police assume that Bentley never shut off the vehicle, which was found running in the closed garage.

“We can’t prove anything other that that,” Muenz said. “The car was running in the garage, so somebody left it running.”

The vehicle pumped the odorless, colorless carbon monoxide fumes into the apartment unit.

The one survivor, Ferguson, told police all she could remember before passing out.

The Jackson County Prosecutor’s Office wanted to make sure police ruled out other possibilities before ruling it as an accident. If police get new information that would put the ruling of accidental into doubt, the Oak Grove Police Department could re-open the case, Muenz said.