The man and woman found dead in a vehicle Friday afternoon in a Springfield Walmart employee parking lot likely died of carbon monoxide poisoning.

Tom Van De Berg, chief forensic investigator for the Greene County Medical Examiner's office, called the deaths "a very sad case."

"It looks like an accident, like a mechanical issue with the car, an exhaust leak," Van De Berg said. "The police and fire (departments) tested it and within a few minutes had a lethal level of carbon monoxide built up in the car."

When the story was shared by other news outlets on Friday evening, many speculated on social media that the two people likely overdosed.

Van De Berg said that does not appear to be the case at all.

Van De Berg said he figures the two were simply sitting in the car talking while on a break from their jobs and "just went to sleep" due to the carbon monoxide in the vehicle.

Van De Berg identified the victims as Austin Holt, 21, and Bethany Weems, 26. They were found in the employee parking lot at the Walmart on South Campbell.

The families have been notified, Van De Berg said.

"(Carbon monoxide poisoning) is not real common, but it does happen. Most often you see it in a house or a dwelling where someone has an unvented heat source," Van De Berg said. "But you do see it occasionally in vehicles."

"That is certainly still pending the official toxicology results," he added, "but all indications from the autopsy suggests that is going to be the end result."

Austin Holt's father, Jeremy Holt, said his son grew up in Idaho. Austin Holt moved to Springfield when he was 20 to live with an older brother.

"They were really happy down there," Jeremy Holt said. "Austin moving down there, he quickly blended in and made friends fast and was enjoying being down there. They were really looking forward to the summer. They had plans to go to the lakes and enjoy the warm weather."

Jeremy Holt said Austin was the fourth of seven children and described him as a happy, outgoing kid who enjoyed the outdoors, hunting, fishing, paintball wars and working on his car.

"He was a sweet kid and a goofball," Jeremy Holt said. "He was the kid that always wanted to be making everyone laugh and have fun."

Austin Holt's funeral will be Saturday in Twin Falls, Idaho.