He had also had an "extended supervision order" imposed on him for the next decade, which meant he would be under strict Corrections monitoring and could be sent back to prison if the order was breached.
Tauranga Detective Sergeant Pete Blackwell was one of the officers who worked on the case at the time and gave evidence at Robertson's trial.
"It was horrendous offending by him," he said.
"He is one offender who concerns me - he is still in denial."
It was "extremely concerning" but not surprising that Robertson had breached his conditions as he continued to deny he had any part in the abduction, Mr Blackwell said.
"Here he is, of no surprise, breaching bail a very short time after he is released.
"He is one offender that I have very, very serious concerns about his re-offending."
Mr Blackwell said he had a more personal connection to the case because Robertson had claimed during the trial that he had planted evidence.
"I will never forget that investigation and that trial that we had. Terrible, disgraceful, appalling."
High Court judge Justice Edwin Wylie last week said he was satisfied Robertson possessed very considerable risk.
"I consider that it is likely that he will commit an indecency on a child under the age of 12 years, and that he will abduct a child for the purpose of sexual connection," he said. "The evidence compels the conclusion that [he] is impulsive, and that he is unable to control his anger and aggression.
"Mr Robertson has a predilection for, and a proclivity towards, sexual offending. He has shown no remorse ... Indeed, he continues to deny it." additional reporting NZ Herald
