(NewsNation) — The brother of a 19-year-old Oklahoma teen found dead along a rural highway says he can’t wrap his mind around the idea that no one knows what happened, suggesting a coverup could be occurring.

Dailen Presgrove told “NewsNation Prime” in a Sunday interview, that the scene where his brother Noah’s body was discovered didn’t match the initial portrayal of a hit-and-run crash. “Some of those injuries, it just doesn’t seem possible that he would have fallen out of a car.”

“There was no tire marks on the street, there was no car parts along the road, his teeth were sitting there next to his face,” Dailen Presgrove said. “If he had gotten hit by a car going 65-70 miles an hour, it just doesn’t make sense that the situation looked like it did.”

Presgrove’s body was discovered wearing nothing but shoes, along a rural stretch of US 81 in Jefferson County, Oklahoma, on Labor Day in 2023. His family says he was last seen alive at a party he attended with a group of friends. The teen had a caved-in skull, road rash on his hip, a gravel rash on his shoulder, multiple bruises and scattered teeth.

While the Oklahoma Highway Patrol said this week it is no longer investigating Noah Presgrove’s death as a murder, his brother believes an accident or “some sort of other sinister situation played out and is now getting covered up.”

Presgrove urged anyone who knows anything, including potential private investigators, to come forward.

“Whether it’s your own story or whether it’s a story of a friend, we please, please encourage you to reach out to us, to the OHP, to … anyone at all just reach out to them with a message,” he said. “As time continues to pass and these interviews continue to play, I know it has to be eating them up inside.”

A former FBI agent is questioning why the investigation into his death is not being treated as a homicide case.

“It doesn’t make any sense,” Jennifer Coffindaffer said Sunday on “NewsNation Prime.” “I understand … there were a lot of people with information. What have they said that makes (police) think that it wasn’t something more insidious?”

Coffindaffer noted the strange circumstances surrounding the case, including an ATV accident Presgrove was involved in before his death, as well as “writings that were actually done on his body that were then removed” and his teeth being located feet from his body.

“So many unanswered questions,” she said. “I’m so surprised that law enforcement hasn’t after eight months … focused in on who the suspects may be.”

“If this isn’t a murder, there is no reason for law enforcement not to discuss with them what happened accidentally,” Coffindaffer said.