The mother of the 7-year-old boy and aunt of the 6-year-old girl told the Bay of Plenty Times she had decided to put the whole matter behind her for her son's sake.
The woman said a car matching the same description as Robertson's had been seen in the same area the day before the attempted abduction.
The morning after the 5-year-old girl was abducted the woman told Maungatapu School's principal about Robertson's approach to her son and niece, and that information was passed onto police.
"It was only about half an hour later the little girl was kidnapped and under an hour later she was found by the detective.
"I was told later this information was instrumental in him finding her."
The woman said her son and niece gave a video-taped interview about what happened.
I thank God that day he protected my little boy and my niece. It's frightening to think what could have happened to them if Robertson had managed to get them into his car.
"I have never really talked about it before as I tried to put it behind us, but talking about it has brought it all back again. It was a very anxious and disturbing time for me," she said.
"I can only imagine what it must have been like for the little girl and her mother as I'm very protective of my children, particularly my two little girls. I really felt for the family of the girl ... It's a parent's worst nightmare."
"I thank God that day he protected my little boy and my niece. It's frightening to think what could have happened to them if Robertson had managed to get them into his car," she said.
"I always felt guilty my son had to walk home from school without me being there, and soon after I put him into after-school care," she said
Over the years she was sent papers inviting her to make victim submissions whenever Robertson's parole hearings came up, but chose not to, nor did she attend his trial because she did not want to see him or give him any more of her time.
"I never really felt like a victim as nothing actually happened to my son and niece. The little girl was the real victim because she was abused by him and I'm sure was left emotionally and psychologically scarred by what happened," she said.
The mother said her son and her niece had grown up to be "beautiful, loving kids" and she would not want them to relive what happened.