An inquest into the death of teenager Mark Haines has revealed new insights from a detective with the New South Wales unsolved homicide squad. Detective Sergeant Peter Rudens stated that after reviewing the evidence, he believes the most likely explanations for Haines' death are suicide or misadventure.

Mark Haines' body was discovered on train tracks eight kilometers south of Tamworth on January 16, 1988. He had sustained a head injury, and the circumstances surrounding his death have been a topic of speculation in the community for decades. Haines' family has consistently disputed the initial police theory that he either committed suicide or laid down on the tracks.

Former lead investigator Craig Dunn testified that he could not accept the notion that the 17-year-old willingly went onto the train tracks.

During the inquest, Detective Sergeant Rudens presented three potential theories regarding Haines' death: a cover-up following an accident, a deliberate act of violence, or the possibility that Haines was responsible for his own death. "I am more inclined with the suicide/misadventure [theory]," he said, suggesting that Haines' death could have resulted from a reckless act, such as lying between the tracks during a thrill-seeking exercise.

Deputy Coroner Harriet Grahame questioned the suicide theory, stating, "Leaving aside misadventure … I can't see any evidence to suggest suicide or an intentionally self-inflicted death." In response, Detective Rudens defended his conclusion, noting that there were several lines of inquiry still to explore. He indicated that further information from Haines' best friend, Glenn Mannion, could be crucial in investigating the possibility of vehicular homicide. "If you could rank persons of interest, Mr. Mannion would be the top one," he said.

Detective Dunn, who conducted an eight-year investigation into the case, shared his working theory involving two similar white Torana sedans. One of these vehicles belonged to Terry Souttar, a Tamworth teenager who later died by suicide. Dunn suggested that the other vehicle was found crashed at the scene of Haines' death. "I think five people were in one of the cars and they came across Mark," he said. "I believe it's death by misadventure and [Mark] was placed on the tracks."

Dunn also revealed that a significant link between the crashed Torana and Mannion emerged only in 2016. Rumors about Mannion's connection to the vehicle circulated in Tamworth shortly after Haines' death. The car was reportedly owned by Mannion's boss, and it was known that the two would take it for joy rides. Mannion has denied these allegations.

The inquest is ongoing as investigators continue to seek clarity on the circumstances surrounding Mark Haines' death.