It was 4am when Ben Clark heard his flatmate leave the front step of his Washington Valley home in Nelson.
"I'm just going to be at one with nature," 19-year-old Leo Lipp-Neighbours told him. Clark did not hear Leo start his orange Toyota Corolla wagon and Leo did not say where he was going.
At 9am, when Clark awoke, Leo was nowhere to be found.
It is four years ago this month that Lipp-Neighbours, a University of Canterbury engineering student, went missing. While foul play was always an option, the pervading theory was that Lipp-Neighbours, described as an introspective and sensitive young man, simply drove off and did not want to be found.
His friends said the night he disappeared Lipp-Neighbours was saying things like "what is it all for" and "life is shit".
His parents, Charlotte Lipp and Colin Neighbours, believed they had missed something in their son. Perhaps they did not realise how much he was hurting inside. They had implored other young people who were feeling down or lonely to keep trying to reach out.
"Be patient," they wrote to the Nelson Mail newspaper.
In September last year, the police inquiry changed. Lipp-Neighbours had likely been in the wrong place at the wrong time, head of the investigation Detective Sergeant Mark Kaveney said.
Tips from the public, that for so long proved fruitless, had led police to believe that someone, unknown to Leo, had harmed him.
Police were potentially looking for a murderer. And, last week, they thought they might have found a suspect.
The morning Lipp-Neighbours went missing, his father wasn't too worried when he got a call mid-morning at his Monaco home from Leo's flatmate, Lewis Christie, wanting to know where Lipp-Neighbours was. He thought if his son wasn't with his friends, he must be at his mother's place.
At lunchtime, Charlotte got a call from Lewis saying Leo had disappeared. She called his phone dozens of times. It was switched off.
His bank account had not been touched and he did not take any clothes with him save for the T-shirt and jeans he was wearing the night he disappeared.
It was assumed he drove off, but whether he turned left or right out of Watson St, no-one knows. After the days and the months ticked over, the family kept searching.
They looked in places where sometimes Lipp-Neighbours would go by himself to listen to music as the sun came up, and down almost-forgotten roads that wound through the Marlborough Sounds. Helicopters covered almost the entirety of the top of the South Island.
The family drove up and down from Nelson to Invercargill. Some people said they remembered seeing Leo's car - all turned out to be false hope.
In the years since Leo was last seen the searches have died down but every so often they will still look - hoping to find something that they missed before.
A $10,000 reward was upped to $50,000. Police had investigated rumours that the teenager's car had been hidden in a shipping container and possibly buried.
They were excited when a helicopter pilot spotted a car covered in bush in the Wairoa Valley. Police bushwhacked to it through a road that had grown over years earlier.
When they found the car it was the same make and model as Leo's, but was yellow. They had followed up the possibility Leo had crashed into the water and had done searches involving dive squads and search and rescue, also in van.
"Foul play" - always part of the potential scenario but which had fallen into the background - came to the fore late last year after a 10-month review of the police file.
Leo did not have any enemies and it was unusual for a young man with such a distinctive vehicle to "disappear off the face of the earth," Kaveney said.
Last week police thought they found someone who knew what happened to him. They raided properties in Blenheim looking for a watch that Charlotte had given Leo for his birthday.
They were also looking for car and engine parts from his Toyota and electronic equipment like cameras and hard drives that might hold more information. According to the warrant, police wanted information about a boat that belonged to a former resident of one of the properties.
There was reason to believe those items could lead to charges of murder, manslaughter or grievous bodily harm.
Police did not find the key items but confiscated computers, DVDs and phones which will be forensically examined. They wanted to check emails to see if anyone had been talking about Leo. Kaveney would not elaborate.
Leo's family could not be reached for comment but have said they wanted to leave it with police. Earlier Charlotte said they had to accept Leo was not alive.
"We think that we've lost Leo, and that we may not find him, and we have to accept that. That doesn't mean we will ever stop wanting to know what has happened to him."
He would have turned 23 this month.
Anyone with information should contact Nelson police on 546 3840 or Crimestoppers on 0800 555 111
- © Fairfax NZ News
Why are fewer teens learning to drive?Related story: Teen non-drivers lazy 'narcissists'