Almost 30 years ago, Mr Towner sexually assaulted four-year-old Sydney girl Lauren Hickson and smashed her head with a rock.
The man then drowned the young girl and dumped her body in an Emu Plains Creek, the The Daily Telegraph reports.
Towner was sentenced to life without parole, but had his sentence changed to include the possibility of parole after 20 years. He has served 28 years of the sentence and could walk free if the State Parole Authority approves it.
Lauren's parents, Derek and Jurina Hickson, told 9News they would like to see the convicted killer stay in prison.
“Children should be protected, but they are not," Lauren's mother said.
"She is not here, not here for Christmas, and she is not at family gatherings.”
Mrs Hickson added: "God forbid what he'll do (if he is released)."
Mrs Hickson also told The Daily Telegraph that her daughter’s killer did not deserve a second shot.
"I'm a mother who has lost a child through the most devastating and heinous crime that this country has seen and I can't understand why he is going to get out of jail,” she said.
This article first published on Marie Claire.