Meanwhile the hunt for the 46-year-old Wanganui man continued into its second night as temperatures plummeted and rain and wind again lashed the area.
Police want to talk to Bourke after a man's body was discovered in a car, a farm worker was shot and wounded near Norsewood yesterday and a policeman was shot at.
Central District Commander Russell Gibson told 3News that between 40 and 50 staff had been at the scene in southern Hawke's Bay for over 24 hours.
They were continuing to search "farms, hay stacks, little implement sheds, milking facilities, forest and scrub".
Helicopters carrying thermo-imaging equipment had also been used in the hunt.
"We have been to a river bank in the last hour or so where we found some of his clothing," Mr Gibson said.
He confirmed police were now treating the discovery of the body in the gunman's car as homicide.
Earlier, part of the police cordon set up to contain Bourke was lifted to enable farmers to tend to their stock.
About 3000 hectares between Norsewood, Ormondville and Takapau, in southern Hawke's Bay was cordoned off in the search.
An area of the cordon at State Highway 2 was lifted this afternoon and farmers were able to return to their farms on a case by case basis.
One farmer told Radio New Zealand that being away from his stock since yesterday was a "huge animal welfare issue" and calves on his farm had died in his absence.
And the farm worker shot by the gunman told TVNZ's Close Up programme he didn't realise he had been hit in the shoulder until he was 3km from the scene.
Chad Hinga said the gunman did not appear to have a gun when walking towards Mr Hinga and his cousin.
"As I got closer, he had a shotgun just in behind his back and me and my cousin jumped out and asked what he was doing.
"He said he was hunting rabbits and he sort of pulled the gun up at us and we jumped in the truck and he fired at us."
Neighbours Brady Wells and Claire Paget also witnessed the shooting.
"The guy pulled up the gun, pointed it at me and then Chad and his cousin then ran behind the car and then `boom!"', Mr Wells said.
Police were working with the man's family in Wanganui trying to find out more about him, Mr Gibson said.
A postmortem on the middle aged man found in the car would be carried out tomorrow.
The drama began after police chased a car driver - believed to be Bourke - who took off after being breathalysed yesterday afternoon.
The car later crashed on SH2 north of Norsewood and shots were fired at a police car which arrived at the crash.
The driver took off on foot across farmland and the body of a man was found in his car, a green Honda Rafaga saloon.
A short time later a farm worker who came across the gunman was then shot in the upper body, but his injuries were not regarded as life threatening.
Residents of Norsewood, Ormondville and Takapau had been warned to stay inside, lock their doors and stay away from windows.
Police had urged farm workers to take extra care as they go about their work and to notify police immediately of any suspicious activity.
Police have issued a photograph of Bourke who was described as European, 170cm tall, stocky build with short greying hair.
It was imperative no one approach him and contact emergency services should he be spotted, Mr Gibson said.
ESR was to examine the Honda this afternoon, while the body in the car had not been identified, Mr Gibson said.
The car, covered in a tarpaulin, was removed from the crash scene this afternoon.
