A 32-year-old Tauranga man was driving his silver Toyota Prado on State Highway 29 in the Kaimai Range about 3am when he struck a person who was on the road, police said.
He stopped immediately to check, about 5km from Tauranga on the lower Kaimai Range, before he was allegedly pulled from the vehicle and assaulted.
He was then placed back into his Toyota and abducted, police said, but escaped from the vehicle a short distance away.
"At one point the Toyota stopped and the victim took the opportunity to escape and raise the alarm,'' police said in a statement this afternoon. The abducted man was treated at Tauranga Hospital for head injuries and later released.
The couple in his vehicle are then believed to have dumped the woman outside the hospital in Matamata, police say.
About 4am, a security officer discovered the 18-year-old woman outside Pohlen Hospital.
About 30 minutes later police in Auckland contacted Bay of Plenty to report that the silver Toyota Prado had been recovered in the Papakura area, and a man and woman had been arrested for unlawfully being on a property.
At the scene of the abduction in the Kaimai Ranges, police found a silver Nissan Wingroad stationwagon, which was stolen from Tauranga Hospital yesterday and appears to have broken down on the highway.
"There is still a fair bit of work to be done and there will need to be a post mortem to establish exactly when and how the young woman found in Matamata died,'' Detective Senior Sergeant Lew Warner said.
"However at this stage we are working on the belief that a chain of events began when the stolen stationwagon broke down or ran out of petrol in the Kaimai Range, leaving the offenders stranded.''
He said the 18-year-old woman had "a number of injuries'' and a post mortem examination would be necessary to "establish definitively whether she was the person who was struck by the Toyota''.
Police have appealed for information from witnesses travelling between Tauranga, Matamata and Auckland this morning who saw the Toyota Prado.
Anyone who saw the stolen Nissan stationwagon in the central North Island since yesterday afternoon should also contact police.
The man abducted in the Kaimai Range told police two truck and trailer units passed by while they were still at the scene on the highway where the woman was struck.
He said he had tried to wave them down.
Anyone with information should call Tauranga Police on 07 577 4300 or Crimestoppers on 0800 555111.
