WARNING: Contains content some people may find upsetting

As Ariki Rigby's loved ones fight for "justice" for the slain teenager, her cousin has revealed that she had been looking to move to Brisbane to start a "new life".

Two weeks have now passed since police launched an "unexplained death" investigation after human remains were found in a burned-out car in a rural carpark near Havelock North.

Days later it was upgraded to a homicide investigation, and a week ago police revealed that the body was that of missing 18-year-old Rigby.

As police continue to follow "strong lines" of inquiry, grieving Brisbane-based cousin Juliana Fitzgerald opened up about Rigby's life, how members of her family "couldn't rest" until those responsible were caught and also spoke of her own intense anger towards whoever killed her.

Fitzgerald also revealed her much-loved younger cousin had been talking about relocating to live with her so she could launch a "new life".

Floral tributes lay at the spot where a car contained Ariki Rigby's body was torched in rural Hawke's Bay. Photo / Neil Reid

"We talked about it for two years," Fitzgerald said.

"We were planning on getting her a passport. She was going to live with me . . . she was going to start her new life and live with my family.

"I know that she was bounced [around] different houses. She didn't really have a stable childhood.

"She was naughty a little bit . . . she was just young and didn't have any stability. That is why she reached out to me and I was hoping to help her out."

Rigby was raised in the Hawke's Bay, and returned there after studying at Whanganui Girls' College.

Ariki Rigby has been remembered by a cousin as being beautiful, happy and loyal to those she trusted. Photo / Supplied

In the months leading up to her death she had moved to Auckland, where her mum lives.

"She was doing really well. She had an apartment, a car and a secure job," Fitzgerald said.

"She seemed really happy. I was very proud of her. I remember her smile, her being so beautiful . . . she was just so bubbly."

Fitzgerald said she told Rigby not to return to Hawke's Bay to live.

The carpark where a car containing Ariki Rigby's body was torched is close to some of the Hawke's Bay's top vineyards and also a popular dog walking spot. Photo / Neil Reid

Just over a month ago the teenager made what would ultimately be a fateful decision to make what was supposed to be a brief visit to Napier to visit friends and family.

During her time in Hawke's Bay, Rigby – who was farewelled by about 700 people at a funeral last Friday – visited Wairoa; a trip a friend claims she came back "angry" from.

One of Rigby's social media accounts included a photo of her posing with patched Mongrel Mob Flaxmere members on August 27.

Family members and friends had been searching for her since they last had contact with her late last month.

Her last contact with her sister was via a text message on August 23, with Anahera Rigby sharing it on social media on September 8 and urging anyone with information on Ariki's whereabouts to contact her.

Tragically, Rigby was already dead.

Balloons and flowers at the carpark in Havelock North where the body of Ariki Rigby, aged 18 years, was found in a burnt-out car. Photo / Neil Reid

The post was made six days after Ariki's body had been dumped in a car that was then torched in the carpark at River Road Recreational Reserve. Police believe the car was driven there between 10pm on September 2 and 7am on September 3.

It wasn't for a further two days that police realised that a body inside the car was human; initially believing the remains were of an animal.

Fitzgerald said she had feared the worst after not getting responses from Rigby.

"I knew that she was missing and the family had been looking for her," she said. "I was starting to get worried.

"I just had a really bad feeling something was wrong. Then on that Monday night my father rang me and told me that they had found Ariki [identified her body] . . . it was terrible."

Anahera Rigby speaks during her younger sister's funeral last Friday which was attended by about 700 people. Photo / Warren Buckland

During Rigby's funeral, cousin and family spokesman Michael Ngahuka called on anyone close to the perpetrators to speak up.

"I hate this. Hate is a strong word - but for this occasion, it is not strong enough. It is gross. It is inhumane. It is traumatic. This is pure evil. This is demonic."

On the eve of the funeral, the well-known Hawke's Bay pastor had told whoever is responsible for the 18-year-old's death that "you reap what you sow" via a post on social media.

The dog walker who found Ariki's body in the torched car said it appeared she had been jammed behind the driver's seat. He also said it appeared she had multiple broken bones.

Talking to the Herald, Fitzgerald said her beloved younger cousin's slaying had left her shell-shocked. Given her distress, she has not been able to work since hearing of the death.

"I am angry, I have had anxiety, I am hurt, I am sad," she said.

"I couldn't go back home for the funeral because I have four sons here and my husband couldn't take work off.

"I have been all over the place [emotionally] . . . I think I calmed down on Saturday. But when I see the articles and get messages from friends and family it just arcs the anger up."

She said it was unlikely she would ever be able to have any forgiveness towards those responsible.

"To be honest, and I hate to say it, but I hope they die," she said.

"My dad is very churchy, he goes to church, and he has forgiven these people and we are having conflicts at the same time . . . because I don't. He is telling me to forgive them, but I am not that person.

Police officers hunting for any evidence a day after an "unexplained death" investigation was launched. Photo / Neil Reid

"Ariki deserves justice and I will do anything I can from here to help that."

Rigby's killing has sent shockwaves through Hawke's Bay and around New Zealand.

Fitzgerald said her grieving family appreciated all the support they had been offered from Kiwis over the past two weeks.

When asked if she believed many people knew exactly what happened to her cousin, and why, Fitzgerald replied: "I do".

"If people have any information, come forward to do the right thing. We can't rest until there is justice, that the people who have done this to Ariki [are caught]. It is hard.

"I understand it will be hard [to come forward]. We would so appreciate if anyone who knows anything came forward and give the information to the police."

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