Fugitive father Tom Phillips was receiving outside help during his years on the run before he was killed in a police shoot-out this week, New Zealand police said on Wednesday as they released images that show a newly discovered campsite.

Phillips had spent nearly four years hiding in the wilderness with his three children. He was killed in an exchange of fire with police after reports of a burglary in the remote town of Piopio, in the central North Island, on Monday.

Later on Monday, two of his children were found safe and well at a campsite in Waitomo. It is understood the third child was with Phillips at the time of the shooting.

After identifying what they believe to be Phillips’ main campsite for the last few months, police said it appeared he had received outside assistance.

“We are currently looking at a number of items at the site. Aside from the burglaries we are now able to link to Tom, it is apparent that he had outside help,” said detective senior sergeant Andrew Saunders.

“As the investigation has been going on, we’ve always suspected Tom Phillips has been receiving help,” Saunders said.

Police would now open a new investigation to identify anyone who helped Phillips. Objects found at the campsite would be analysed to see if they could be linked to burglaries or had been purchased for Phillips.

“We think it’s absolutely important that we continue to look for those people that have been supporting Tom Phillips and hold them accountable.”

Images of the campsite released by New Zealand police on Wednesday. Photograph: New Zealand Police

The pictures released on Wednesday show a campsite found roughly 200m from the site where his children were discovered, police said in a statement.

The images show a steep incline where tarpaulins have been erected among the trees. Camouflage netting covers one corner of a large structure. Inside the campsite is a gas cylinder, a portable stove top, large buckets, gumboots and a tent that looks to be set into a dugout area.

It was difficult to access, well-hidden and highlighted the challenging environment the family used as its base, they said.

“It’s a very grim, dimly-lit area, surrounded by dense bush. The tent was well covered and dry,” said detective Saunders.

The campsite was “very dirty”, cramped and “not very nice for children”, he told media on Wednesday afternoon.

The site was likely Phillips’ main campsite in recent months but not necessarily the primary place the family had lived in since they vanished, Saunders said.

Images released on Tuesday showed the campsite where two of Phillips’ children were found. Police said at least one firearm and ammunition were discovered at the campsite, about 2km from where Phillips had been killed. A police officer is recovering in hospital after being shot in the head by Phillips with a high-powered rifle in the standoff.

Tarpaulins have been erected among the trees at the campsite. Photograph: New Zealand Police

Phillips took his children Ember, now 9, Maverick, 10, and Jayda, 12, into the Waikato wilderness in December 2021 following a dispute with their mother. Phillips did not have legal custody of his children. He was facing a raft of charges, including aggravated robbery, aggravated wounding and unlawful possession of a firearm. Experts have expressed concern about the children’s reintegration into society.

The children’s’ mother, Cat, told Radio New Zealand’s Mata programme that she did not yet know when she would be reunited with her children.

Police minister Mark Mitchell told Mata it was a “complex situation”.

The children are now in child protective custody. An urgent suppression order was granted in the high court in relation to aspects of the case on Tuesday evening after an application by a lawyer acting on behalf of the Phillips family.

On Tuesday, Warwick Morehu from Oranga Tamariki told reporters the children were settled and “doing well under the circumstances”. He described the situation as “unprecedented” and appealed to the public to give the family privacy.