A Masterton man has been found dead in the Wairarapa Hospital carpark.
Detective Senior Sergeant Barry Bysouth said a man in his mid-30s was found in a parked car in the main hospital carpark at about 8.30am on Friday.
Police had initially treated the death as suspicious and had cordoned off the area surrounding the vehicle, he said.
However a post-mortem revealed the man, who had a pre-existing heart condition, had suffered a heart attack.
The man was found in the driver's seat of his own vehicle with the key still in the ignition.
He was noticed by a doctor who was leaving to go home, Mr Bysouth said.
It was not clear when the man had arrived at the hospital.