More than two months on from the grisly – and belated - find of the body of teenager Ariki Rigby in a burned-out car, police say they are “confident” those responsible will face justice.

On September 5, a dog walker discovered the body of the 18-year-old in a car that had been parked up and then torched at Napier’s River Rd Recreational Reserve two days earlier.

Police initially attended the scene on September 3 but did not identify the remains – which had shoulder-length hair and a necklace – as human.

Despite repeated calls for information from police and Ariki’s traumatised family, those who committed the crime - which has been described as “cruel” by her sister - remain at large.

But investigation boss Detective Inspector Dave De Lange said he was hopeful that the killer, or killers, would be found.

“Police are continuing to make good progress as we investigate the tragic death of Ariki Rigby,” he said.

“For operational reasons, we are not in a position to comment on specific details at this stage of our investigation.

“While some investigations can be more complex than others, police are confident that we will identify and hold to account the person or persons responsible for Ariki’s death.”

A memorial garden with written, floral and solar light tributes to murdered teen Ariki Rigby has been erected at the River Road Recreational Reserve carpark. Photo / Neil Reid

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De Lange said police are keeping Rigby’s family fully updated as the investigation continued into its third month.

The investigation team was still working through “a large amount of information and piecing together the events leading up to Ariki’s death”.

“We continue to encourage anyone with information to come forward and thank those that have already,” he said.

Because of the nature of the investigation, De Lange said he could not comment specifically on a raft of questions the Herald put to him.

They included whether officers thought Rigby had been killed by one person or multiple people, how many potential suspects had been identified, if the homicide was gang-related, and whether people were protecting those responsible, including helping them evade being caught by police.

He wouldn’t be drawn on how many officers were actively working on the case.

And De Lange also wouldn’t comment on the review relating to the handling of the initial inspection of the burned-out car, when officers missed the charred body inside it was human.

The Herald previously revealed the officers thought the remains were of an animal.

It wasn’t until a dog walker rang them again two days later – horrified to discover the body had shoulder-length hair and was wearing a necklace – that police launched an “unexplained death” investigation.

The dog walker also said Rigby had multiple bone breaks and fractures.

During an emotional appeal where she urged those who knew who killed Rigby and knew where they are, her older sister Anaherā Rigby told the Herald she believed the teen was beaten to death before being dumped in the car.

“She would not have stayed in a car while it burned,” she said of her sister, adding she was a very determined person.

“I said that to the police too. I told them she must have already been dead before they torched the car.”

But Anaherā Rigby believed her sister would have fought for her life.

She was disgusted at the actions of her sister’s killers.

“To me that is cruel,” Anaherā said.

“My baby sister didn’t deserve to die like that. Even if she wasn’t my sister, nobody deserves to die like that ... beaten up, shoved in the back of a car and then torched and then left there.

Messages of love have been written on metal fence railings at the spot where Ariki Rigby's body was found in a torched car. New Zealand Herald photograph by Neil Reid

“They tried to cover it up and get rid of all of the evidence and now they’re walking around free.”

She had also urged those who knew the truth to contact authorities, saying her sister’s killers were “dangerous people” who needed to face justice.

When asked what her message was to those who know who did it, she replied: “Not to hide them anymore. People know something, they do, and they are just too scared to say who they are, and what they have done.

“Maybe they love these people and they don’t want to turn them in. But they need to remember that those people are dangerous ... they took a little girl’s life, she was only 18 years old ... she had a whole life in front of her.

“Our community isn’t safe with them walking around, even if they are your family or your friends. They could do it again.”

Ariki - born and raised in Hawke’s Bay – had lived in Auckland for the past year.

She was killed during an unplanned holiday back to Napier.

“She was going to go and see our little brother in King Country, but he wasn’t home, " Anaherā said. “So she changed her mind and went to Hawke’s Bay instead.”

She spent a month in Hawke’s Bay.

“That very day that they did this to her, she was supposed to come home,” she said.

“She even put a status on Facebook that she was coming home and whoever wanted to come and visit her to see her before she left [for Auckland].”

Family of Ariki Rigby have placed flyers in shops around Hastings and Flaxmere appealing for information. Photo / Neil Reid

Family members have been proactive in trying to uncover information that could lead to arrests, including putting up flyers around Hastings and Flaxmere.

The A4 sheets of paper feature two photos of Ariki, with the message: “Any information on Ariki Rigby’s death would be much appreciated.

“Family want, and deserve closure. We won’t rest until we do. We’ll find out who did this to our girl. You didn’t deserve this!”

The flyers include Crime Stoppers’ tip line where anonymous tips can be made.

Anaherā said any information the family received was reported straight to the police.

- Anyone with information is asked to contact police on 105 quoting file number 220905/1265. Information can also be provided anonymously to Crime Stoppers on 0800 555 111.