A post-mortem examination is due to be conducted today on the body of a boy, believed to be Alex Fisher, which was located on Waitarere beach yesterday.
Police released the update on their investigation in a statement to media this morning.
Arrangements for formal identification are being made, said the statement.
The investigation was expected to continue over the weekend, with 20 staff working to find out what happened to Alex.
Detective Senior Sergeant Neil Forlong said a number of "items of interest" were also removed from the scene with the boy's body, but would not be drawn on what those items were.
"While this is a homicide inquiry given the suspicious circumstances involved, we are keeping an open mind about exactly what has occurred," he said.
"We are however building a good picture of the events which led to the boy's death and it is important for the community in Waitarere to know that we do not believe there is any wider risk involved.
"We are aware that there is some speculation and rumour regarding the tragic events of the last few days.
"The purpose of the investigation is to establish the facts, and methodically gather all the information and evidence needed.
"We still want to hear from anyone who saw Alex Fisher or his brother Eric."
Mr Forlong said police also wanted to hear from Waitarere community members who may have seen or heard anything suspicious or unusual on their properties.
"We are mindful that the community is very shocked at the events of this week.
"We will obtain all the information we need for the coronial process and any possible judicial process which may follow, and ultimately establish the facts for the family and wider community," he said.
Forensic scientists remain at the scene where Alex was found.
Police officers are guarding the cordon, on vegetation-covered sand dunes, but there are no restrictions on people wanting to drive on Waitarere Beach or on local streets.
A local man familiar with the beach properties said everybody in Waitarere he'd spoken to was shocked.
Alex's death cast a "sombre" mood over the whole community, he said, at a time when Waitarere was normally a happy place with people enjoying the school holidays.
The homicide seemed completely incongruous for a peaceful place like Waitarere, he said, "but it can happen anywhere".
"The worst outcome"
Family, friends and the searchers worked tirelessly searching thousands of hectares, through the forest, above the forest, in streets and across hundreds of backyards for Alex.
In the end, it was "absolutely the worst outcome", said Manawatu area commander Inspector Sarah Stewart.
His family were "devastated", she said, after personally delivering the news to them.
This morning, around 8.30am, the curtains were drawn at the family home.
A sign requesting privacy was placed outside the fence, beside the driveway.
Ohau School principal Kathy Trevena Brown said she would meet with the family today.
Alex's family learned shortly after 1pm yesterday their boy was believed to have been found dead.
Ms Trevena-Brown said the school community had "lost a lovely member of our family" and "missed him dearly'.
In a statement about "the tragic loss of our lovely Alex," Ms Trevana-Brown said: "Alex was a delightful student who did find some aspects of school life challenging but he was up for it.
"He was determined to give everything his best shot.
"He didn't give up and persevered."
She said the school was "so proud of him".
"He was such a polite well-mannered boy, who involved himself in school activities. He was a member of our Kapa Haka group, and he was in the softball, basketball and water polo teams."
She said student and parents were being supported.
School representatives would be meeting with the family today to discuss being involved in Alex's funeral or memorial.
"Our children will be able to prepare some memories such as school photo albums put together for the family. This will give them a positive focus as we move forward."
Police Commissioner Mike Bush has extended his sympathy to Alex's family.
"Our thoughts are with the family of Alex Fisher following yesterday's tragic news," he wrote in his weekly blog, published today.
"I would like to thank the Central District police team and all the search and rescue volunteers, including New Zealand Defence Force staff, who worked tirelessly over the past few days to look for Alex.
"We all hoped to find Alex alive and we all share the grief of his family and community."
Community rally to help family
Tributes are continuing to flow for Alex, as the community rallies around his family.
A number of fundraising initiatives to support his family - including a food drive and a Givealittle page - have been created and some business have even erected signs showing their support.
"Let's help Alex Fishers family during this absolutely tragic time," the Givealittle page reads.
"Nothing can bring their boy back but we can try to ease their load. Please donate anything you're able to spare. All Funds will go to his immediate family to help them with any on-going financial costs that come with dealing with the loss of their child."
Levin woman Mel Hailliday is behind a food drive for the Fisher family, and said she was astounded by the number of people donating.
"Once I heard he was missing I decided that we needed to come together to get some food for the family for when he got home.
"At that point we all thought he was lost, but once the news broke yesterday that his body was found the donations became probably 50 times what they were before."
Everyone was in shock and wanted to do what they could for the family, she said.
"This is what you see on the news in Auckland, it isn't something that happens around here. Waitarere is the most beautiful place.
"He was just a lost boy in a forest trying to find his way home, that's what everyone was banking on. Because he was a Scout and knew what he was up to, he just would have taken the long way home."
Messages of support are also being posted online.
"So sorry to hear that Alexander has been found in the worst possible way," said Janine Wilson on Facebook.
"I send my condolences to the Fisher Family [sic]. Come on Levin help the family out!"
Helen Maree Kirkby said: "Rip young man taken away from your family way to soon thinking off your family at this very sad time [sic]."
A public vigil for Alex is to be held on Sunday at Waitarere Beach.
Man appears in court
A local man appeared in the Levin District Court on Wednesday on a single charge of possessing a knife in the area where the search for Alex was focused.
He was granted interim name suppression and remanded in custody by consent. The court heard at least one further, unspecified charge was likely.
Alex was found just south of the main beach entrance in the tight-knit Waitarere community of 500 residents.
Last night, in front of the beachside houses, with Kapiti Island in the distance, the body was removed soon after sunset.
Earlier, forensic scientists scoured the area. Police stopped traffic along the beach and talked to members of the public.
A resident said the locals were feeling spooked. Her beachfront property looks onto the site where the body was found. She had not seen anything suspicious.
"We all watch out for each other but I never saw a thing. It's close to a walkway that has been regularly used over the last few days."
The search had been centred on Waitarere Forest, but she knew Alex was not there because "no one could get lost in there".
The last confirmed sighting of Alex was at the Waitarere Four Square on Monday night with his adult brother Eric.
Last night, its staff echoed the description of the community as being full of people who looked out for each other.
It's unknown why Alex was in Waitarere. He lived with his parents about 10km away in a quiet residential part of Levin with modest houses and wide streets.
A woman who lives a few doors from Alex's family said the 10-year-old was not the kind of boy to run away.
"He's just a normal happy boy. He's always smiling, always polite. His parents love him to bits. He's their baby."
Alex was a student at Ohau School, just south of Levin. Its August 2014 newsletter reports he won a bus award.
He was also a member of the 22-strong St Mary's Scout group in Levin. Scout leader Barry Fitzgerald said Alex was a "typical 10-year-old young fella", eager to learn and enthusiastic about Scouting. The wider community also paid tribute to Alex last night.
A community in mourning
The Boardroom bar on Oxford St, Levin, has written "RIP Alex Fisher" in large lettering on its main-road facing signs.
Duty manager Hayden Davidson said the whole community was devastated by yesterday's news.
"Everyone is feeling it, it's affected everyone. He's only 10 years old, he hadn't even started living his life yet, and the heartache of losing a child, that must just be absolutely unbearable."
Mr Davidson did not know the family, but the bar had set up a donation box, which was filling quickly.
More than 130 people, many of them locals, helped look for Alex.
Yesterday morning, police were still treating the operation as a search and rescue, and had not given up hope of finding him alive.
But more than 60 hours after he went missing, there were serious, growing concerns for his health and safety.
Mid-afternoon, police told media about the sad discovery, after Ms Stewart had visited Alex's family.
Despite the find, police still have plenty to do, she said, appealing to anyone who saw Alex and Eric on or before Monday night to get in touch.
"Our investigation is likely to take some time as we build up a picture of the events that have led to this tragic outcome."
- Manawatu Guardian, NZME