A justice advocate says the parole system needs to understand the perspective of victims when deciding on an offender's release.
Ruth Money was speaking to The AM Show about Paul Russell Wilson, who served 15 years in prison before being released on parole in 2011.
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Wilson raped and murdered Nicole Tuxford in her Merivale home in April 2018, after waiting for her for eight hours.
Ms Money was highly critical of the decision to release Wilson and said some people need to stay behind bars.
"We don't accept that some people in society are psychopathic monsters and jail is the only place that will keep us safe from that."
She said it's hard for people to understand the victim's feelings in dealing with parole hearings, which many turn up to out of a sense of duty.
"People don't understand the trauma... and the pressure that these victims feel to stop this happening to other people.
"I sit with academics and they ask homicide families 'why are you going to the annual parole hearings, you know you don't need to go to the annual parole hearings right?'
"They just don't understand that these families are so vested in this never happening to anybody else. No-one else should suffer like this."
Wilson's parole was vigorously opposed by the friends and family of Kimberley Schroder, who he raped and murdered in 1994.
"I personally said to them you cannot let this man out, he will do this again, he will kill again," Ms Schroder's former best friend Jenny Keogan said at the time.
The devastation was too much for Kimberly's father, Gary Schroder. Three days after finding out Wilson had killed again, he is suspected to have taken his own life.
"I predominantly blame Gary's death on Wilson murdering again," Ms Keogan told Newshub.
The New Zealand Parole Board announced on Thursday clinical psychologist Professor Devon Polaschek will conduct an independent review on its handling of Wilson.
Prof Polaschek has done research that found early release on parole, combined with intensive psychological treatment, is effective at reducing reoffending among high-risk prisoners.