In all, it is 14km of winding road from the farmhouse where his brother Arthur and sister-in-law Vivien slept on the night police alleged Arthur murdered the Crewes.
The word Pukekawa translates to "Hill of Bitter Memories". The bitterness remains but everything else in this ugly tale has changed with the years.
Des Thomas spent his childhood here. He was a teenager who grew up fast as the horrified scrutiny of a curious nation was directed at his older brother Arthur. As he became a man, he learned to never again trust the police without question. If anything, the passing years have allowed the feeling of betrayal to fester and grow.
The house where the Crewes died is there, he says, pointing. A dog barks at the gate and children run down the drive to see the car that has stopped outside. The road loops around the hill and down to the Waikato River.
Here, he says, is where the bodies went into the water. "Chris Birt thinks they went in further down," he says, pointing out the place suggested by the author whose book, All The Commissioner's Men, led to Des sitting down after all these years and writing to Police Commissioner Peter Marshall to ask for justice.
The police got it wrong - that was the finding of the royal commission of inquiry into the murder conviction of Arthur Thomas.
Not only that, but they found there had been no justified reason to arrest and prosecute Arthur Thomas.
How could it be, Des asks, that so many people had their lives pulled apart, his brother jailed and - he believes - his mother dying early, without someone taking responsibility?
The findings of the royal commission into the arrest and prosecution raised questions about the way the police handled the case. The lack of answers has had a corrosive and persistent impact on the police ever since.
In Des' opinion, crimes other than murder were committed. Should the police not prosecute those, he asks.
Look at this, says Des, sitting at his dining room table. He unbundles the file he sent to Peter Marshall; carefully catalogued and separated by orange, yellow, green, blue and grey cards are the six complaints of criminal behaviour he wants police to pursue.
"It is easy to understand," he says. "It is in a form a child could understand."
The intricate details of evidence from the case are disappearing with time. Those who knew the details of the axle, the wire, the bullet and the cartridge case that conveniently emerged in a garden that had already been searched are fewer every year, such is the length of time to have passed.
Des Thomas' complaints don't turn on details. They deal more broadly with the oaths sworn and documents signed by police which underpin the public faith that they will act with honesty. The collective might of the police is balanced by the trust that officers will not use their powers unfairly against the comparative weakness of the individual citizen. Set against the oaths sworn are the findings from the royal commission that those oaths had no substance. "(Arthur Thomas') arrest and prosecution for (the Crewes') murder was not justified."
"It's not fixed up," says Des. "This new commissioner, Marshall, he keeps going on about transparency. Well, where is it?"
His file was posted to the commissioner on October 20. A letter acknowledging receipt arrived about a week later. Police have told the Weekend Herald it is currently being "assessed", a preliminary phase to a criminal inquiry.
"Arthur doesn't want anything to do with it," says Des. His brother is living his life, having lost enough years inside prison. Brother Richard Thomas is involved, though, and Des has written to Rochelle Crewe, who emerged two years ago to ask that her parents murder be investigated, to tell her of his plans. Her request sparked a review of the case by one of the country's most respected criminal investigators, Detective Superintendent Andy Lovelock.
"At the end of the day, I don't want the police to be pulling the wool over her eyes," he says.
Des Thomas and many of those who formed the Arthur Thomas Retrial Committee have little faith remaining.
They have read in newspapers about Louise Nicholas and allegations (not proved in court) that she was raped by police. More recently, they have read how senior police in Nelson were implicated in manufacturing false court documents and swearing a false oath in a gang inquiry.
If there is a lessening in faith, then it can all be traced back to the Thomas inquiry, says Pat Vesey, the founding chairman of the retrial committee.
He calls the period until the end of the royal commission "soul destroying", for the life and opportunity overtaken by pointless struggle. "Time that could have been devoted to other things," he says.
The fight for justice stole time too. Arthur Thomas' wife Vivien (later Harrison) died in Australia last year. She was Mr Vesey's niece; he introduced the couple. This spring, he buried her ashes in Northland. "It shortened her life by years," he says. "Nothing shortens life like stress." Mr Vesey had met her off the boat from England. "I was responsible for her. It hurts, what she has gone through."
In the years in which so much effort went into freeing Arthur, and in the years since, Mr Vesey and others tied so closely to the case have pondered deeply what it means. The events they lived through were so contrary to their belief, that it needed consideration to be properly understood.
Friends would say, "Don't let the ghost of Arthur Thomas' conviction haunt you for the rest of your life." But Mr Vesey says there was a wrongness to it which has never let go.
"People volunteer to go to the police because they want to help make New Zealand a better place to live. I grew up respecting the police, my father, the headmaster - people in authority. You trusted them entirely."
And, he says, he's not "anti-cop". There has been his involvement in Search and Rescue. "I've worked with some hell of a good cops."
He believes the Crown should have laid charges against the officers leading the Thomas inquiry as soon as the royal commission was over, as those police had "besmirched the profession". "They weren't prepared to look at the evidence and they still are not. Nobody has been prepared to clear up this mess. They think it will besmirch the police." Doing nothing, Mr Vesey says, is worse.
Des Thomas says Arthur's case is important to every New Zealander. "It is the one case that has made every person question the attitude of police." He watched as his father was crushed when he realised the help he gave police was being wrongly used as a weapon against his son. He believed the impact of Arthur's second trial directly affected his mother, who stopped speaking and never walked again.
"You get to the stage where you get angry. You get to the stage where you think, 'This is not right.' This is the case that has been the big wake-up call about not trusting the police. This all has to be opened up. Rochelle talks about a festering sore. It's about time it was lanced open."
The police clearly understand how important it is to have the trust of the public.
The formal instructions for police internal investigations "recognises the most critical asset of the New Zealand Police is its reputation", according to the report of the Commission of Inquiry Into Police Conduct, which looked into the allegations made by Louise Nicholas and others alleging sexual misconduct by officers and an institutional unwillingness to investigate it.
"This is achieved by setting high professional standards and demonstrating to the public, through a willingness to be held accountable for breaches of those standards, that the police deserve the public's trust and confidence."
The police have changed to meet the public's blind faith of previous years with a structure that aims to justify that trust. A Code of Conduct followed the inquiry into police conduct and formalised obligations of honesty and integrity, fairness and respect for the people they deal with.
Assistant Commissioner Mike Bush, seen by some as the next police commissioner, was clear about the focus on public expectations in a recent radio interview given after officers were accused of a "fraud" on the court: "We want to maintain and grow that trust and confidence because it makes us do a better job."
Police have measured public "trust and confidence" for the past five years. In the interview, Mr Bush said the recent 77 per cent rating was "the highest I think it's ever been".
He's right - the figure has climbed since polling was instituted.
It doesn't reflect the belief the public have less faith in the police than in the past, which retired detective chief inspector Rex Miller, a veteran of 37 years - with no connection to the Crewe murder case - puts down to changes in society rather than police.
"I think police are still held in pretty good regard. The ones who are anti (police) are usually the ones who have done something wrong."
Miller says that, contrary to what some people might suggest, there is no tolerance in the force for bad behaviour, rule-breaking or malfeasance. If there is wrongdoing, it will be examined and rooted out if it can be.
"I did internal inquiries for years. They are more severe on their own staff," he says. "They are certainly not white-washed. People think you look after your mates but you have to do it properly. There is no sweeping under the carpet."
Miller had an early brush with the case involving allegations made by Louise Nicholas. His testimony years later in 2007 helped convict former Rotorua CIB chief John Dewar on four charges of attempting to obstruct or defeat the course of justice.
Police handled 130,000 prosecutions last year. Even the lowest of error rates will still make headlines. The media, too, have a role in the perception of the police, says Miller. "Good news stories don't sell newspapers."
Pukekawa fades into the rear-view mirror, changed as New Zealand has changed. Milking sheds stand empty and broken as small dairy holdings have given way to large dairy co-operatives, edging out the sort of farm on which the Thomas boys grew up.
Market gardens have taken their place. Farming here used to mean watching the sun rise and set with morning and evening milking. Now, farmers shield their faces, spending their days looking down at crops.
The change is written across Des Thomas' face, along with anger and frustration. He wants police to carry responsibility for their role instead of simply wearing the blame.
"It's a disgrace," he says. Somebody needs to have the guts to say: 'Let's clean this thing up from one end to the other. The murders and the malpractice. It's all about justice, in the end."
