Dangerous offenders like Tony Robertson regularly breach special court orders meant to keep them under close watch after being released from prison.
Of the 46 released child sex offenders ordered by the court to submit to being electronically monitored, more than half have breached the conditions of their Extended Supervision Orders (ESOs).
It's an exclusive club of which Robertson is a member - electronic monitoring is for child sex offenders considered to be the most dangerous at the time they are released from prison.
Robertson was subject to an ESO at the time he killed Blessie Gotingco because of psychological reports indicating he was high risk and a refusal to undertake treatment programmes during an 8-year term in prison for child abduction and molestation.
He was not subject to the ESO at the time of the murder of Blessie Gotingco because he was subject to similarly restrictive release conditions set by the Parole Board when he was released in December 2013.
The ESO was sought by the Department of Corrections and due to come into force for 10 years from June 2014.
Figures obtained through the Official Information Act show the the Department of Corrections obtained 140 Electronic Supervision Orders until August last year. The figure would have included the order granted against Robertson in March 2014.
The total was reached after 10 years of the law allowing ESOs being in force. It was passed by Parliament in 2004 and peaked at 242 child sex offenders, of which 26 were in custody in November 2014 for breaching the order or fresh offences.
The average cost of monitoring an offender subject to an ESO is $27,000 a year although costs vary. It stated those under the most stringent Parole Board conditions could cost $300,000 a year.
The figures show a drop from 38 people given an ESO in 2009-10 to 18 in 2013-14, which Corrections says is due to the "finite" number of those in the community who qualify.
ESOs were considered for those who showed the highest level of potential risk, and always for those who refused to accept any treatment.
Victoria University Professor Tony Ward - formerly Director of the Kia Marama Sexual Offenders' Unit at Rolleston Prison - said sex offenders reoffended at a "significantly lower rate" than other people released from prison.
He said those under the ESO regime needed support on release to avoid isolation - a prime factor in re-offending.
"The problem with demonisation is it isolates the person from the community. The best way to keep us safe is to keep an eye on someone."
Support included making therapy available, encouraging employment opportunity and involvement in community groups. He said the closeness of the community around a released sex offender made it more difficult for that person to offend.
"The public understanding of sexual offending is so poor that they think people are walking around with this destructive potential for sexual offending that's just seconds away."
The University of Auckland's Dr Gwenda Willis said media skewed perceptions of sex offenders and gave people an unrealistic fear of stranger-danger.
"The cases do happen but they are rare. People around you are probably a greater risk than someone who has been in prison."
She said the 140 people who were subject to ESOs gave no insight into those in society who had not been caught - and most child sex crimes were committed by people known to victims.
Dr Willis said risk scales were not absolute measures. "There's no way we can say 'this person is (a certain) per cent likely to reoffend'. It would be nice if we could predict but it's not that straight-forward."
She said the measures was relative to others who were committing the same sort of offending.
2009/2010
ESO approved: 38
ESO breaches: 23
Electronic ESO: 14
Electronic ESO breaches: 100/2011
ESO approved: 29
ESO breaches: 11
Electronic ESO: 9
Electronic ESO breaches: 61/2012
ESO approved: 33
ESO breaches: 20
Electronic ESO: 9
Electronic ESO breaches: 62/2013
ESO approved: 22
ESO breaches: 7
Electronic ESO: 6
Electronic ESO breaches: 23/2014
ESO approved: 18
ESO breaches: 11
Electronic ESO: 8
Electronic ESO breaches: 6
By David Fisher of the New Zealand Herald