But they soon discovered dealing with Guthrie comes at a price. Bank transfers show the family paid Guthrie at least $9058 over several instalments.
Family spokeswoman Donna told RNZ Checkpoint that money came out of people's life savings.
"We drew money out of [KiwiSaver] which was worth retirement fund money.
"It gave me the impression that it was a charity. He told us that he worked for the Sensible Sentencing Trust. He told us he worked for the [Transforming Justice Foundation]. And they were all trusts. (Guthrie is no longer with either trust).
"So we were led to believe that this was a trust and that he was just the person that was out there doing the job and helping everybody he could possibly help within the system of Corrections.
"I want them to pay back the money. I want him to give every cent back."
Scott Guthrie has said he advocates for a fairer prison system; guarding against the abuse of prisoner rights and holding Corrections to account.
At the time he met the family he was involved with the registered charity Transforming Justice Foundation. Guthrie was reportedly sacked by trustees in January 2021 and the charity was deregistered in April.
Since then Guthrie has operated under the banner of Justice for Kiwis.
Scott Guthrie defends charging inmate's family thousands of dollars
Speaking to Checkpoint, Guthrie initially defended the fees he had charged the Northland family, citing travel from his home in the South Island up to Northland to visit the family, the man in prison, and the time involved to prepare his appeal.
But he said what he is doing is "certainly not a business".
A copy of an invoice from Guthrie which the Northland family gave to Checkpoint shows he charged them $10,000 for "support and advice," and "consulting with Corrections".
Initially he denied the invoice existed. "That would have to be totally incorrect. You'd need to send me a copy of that because I would refute that absolutely."
Once Checkpoint's Lisa Owen explained the invoice had his correct name, address and contact details, and had come from his email address, he acknowledged the invoice existed.
"When I'm looking at my invoices now you are correct, but that invoice was withdrawn and the new one was drawn up, because $4000 was kept aside so we could get a psychologist's report for the inmate heading towards an appeal."
He said there were three invoices to the family. The original was withdrawn, and two more followed that.
Guthrie said his invoices differ according to "who can afford what" and how much time he spends working on a case. He said he has billed "two or three" families for support and advice.
"I've been up to see that family three times in Kaikohe … also the time I've spent with their son in prison, the hours I've spent talking to Corrections officials about getting him out of segregation, getting him placement, the work I'm doing with the appeal lawyer, going to court hearings when he was sentenced."
Guthrie denied that Justice for Kiwis was a charitable organisation. "It is not charitable, it is not registered. We have never made this statement."
However, in two of his invoices to the family, Guthrie used his Transforming Justice email - the charitable organisation he used to be part of.
"At the time when I first engaged with that family it was coming from Transforming Justice, yes," Guthrie acknowledged.
But the bank account on the invoice was not the trust account for Transforming Justice. Guthrie confirmed it was his private bank account.
In response to the question of whether he would pay the $9058 back to the family, Guthrie said: "I've got no issue with that at all."
In June 2021 Corrections granted Guthrie what is called specified visitors status, meaning he can go into jails, help inmates get ready for release and parole hearings.
But the law prohibits visitors of this kind taking any money or reward from or on behalf of any inmate.
Corrections has now suspended Scott Guthrie's visitor status, pending the outcome of an investigation.
In a statement to Checkpoint, Corrections National Commissioner Rachel Leota said: "Families should not have difficulties engaging with Corrections - we have an obligation to be accessible and responsive.
"I encourage any families who have worked with this individual to contact Corrections at info@corrections.govt.nz. I will contact them personally and work with them to resolve any issues they have experienced engaging with Corrections."
'He is a dangerous person' - whānau spokeswoman
The inmate's whānau in Northland contributed from their life savings to pay Guthrie's invoice.
"We all pulled together to come up with the money and it wasn't easy, it was hard," family spokeswoman Donna told Checkpoint.
"Basically he rang up and said, could we pay for his flights up so he could meet with us and go in to see a family member at the prison.
"We were happy to do that. Then when he got up here, he sat down and he discussed all the things that he can do for us.
"We were thrilled because we didn't know where to turn or who to ask for help. And during that time up here he said this could cost more money.
"Later on when he came up the next time, he asked again. I said: 'I don't have the money, I will have to ask around again.'
"We asked the whānau. They said they would come up with the money.
"Then he just kept ringing and ringing and ringing, saying: 'What's happening with the money?'
"He rang a particular family member… directly and asked him for the money. He asked him for $10,000 and he was given $6000.
"Then he asked for another $10,000 on top of that and we definitely said no."
Donna told Checkpoint Guthrie gave her the impression he was working in a charitable capacity.
"I feel I've been deceived. I feel absolutely gutted for my whānau. I feel gutted for the people that he says he's going to help. I just feel ripped off.
"I want them to pay back the money I want him to give every cent back, because everything he promised has never happened." she said.
"I believe there's probably other people out there that are in the same boat as us, and when you're going through the justice system and you don't know what to do, you are very vulnerable.
"People in prison are very vulnerable and they latch on to him because he can talk and gives you all the hope.
"In reality it's all talk and no action."
Donna's message for anyone approached by Guthrie for justice advocacy work is to "stay clear".
"Stay away from him, he is a dangerous person."
