They are men who have been entrenched in gang life and never thought they would want to change, let alone could.
But with his perseverance and tikanga Māori, Macfarlane has seen 20 men successfully make it through his programme and turn their lives around.
The Rotorua Daily Post featured the stories of three of those men on Saturday, most notably, Joseph Herbert, who was praised at his sentencing by Judge Tony Snell for his "outstanding progress" in the year he had been on Macfarlane's course.
Former gang members Te Rongopai Waiariki and Corey Anderson also revealed the life-changing strides they had made through Pūwhakamua and their goals to mentor at-risk youth to stop them taking the path they took.
When I sat down with these men, I was under no illusion of what they had done. I wasn't there to make them out as saints or paint a picture that wasn't truly there.
But the stories I was told were not ones of macho bravado and apathy but ones of loss, trauma, loneliness and pain.
It was clear that yes, these men were criminals, but they were also broken and in need of help.
And they weren't getting that while stuck in the toxic cycle of committing crimes and going to prison.
It wasn't until they had hit rock bottom and were picked up by the Pūwhakamua programme that they were given a chance to take another path in life.
Before speaking with these men, I was sceptical such established criminals were capable of change.
But Macfarlane is proving, to me and others, that with the right approach, guidance and ongoing support, it is not only possible but probable.
It makes me wonder why the justice sector is not looking at Pūwhakamua as a prototype for more programmes with the same philosophy across the country.
The evidence that locking people up does more harm than good is overwhelming.
But here is a programme that is successfully taking people out of prison and rehabilitating them.
It's providing the justice system with a suitable alternative to prison and it is one that should be explored beyond Rotorua and Te Arawa.
When dealing with criminal behaviour, we have to be realistic that we're not going to be able to save everyone and Pūwhakamua is not a programme that will resonate with every criminal.
But Macfarlane's 95 per cent success rate shows us it's a concept worth exploring.