Joan Isaacs, pictured with husband Ian (left) sons (left and centre) and her brother (right), appeared at the Royal Commission into Institutional Responses to Child Sex Abuse in 2013.

Aged just 15 and full of shame and fear, the young Joan bravely revealed the months of grooming and sexual abuse she experienced at the hands of local priest Francis Edward Derriman.

But despite reporting it, nothing happened, then there was silence — and lots of it.

What began as a fight for justice turned into a 40-year battle for the truth after endless stonewalling from the Catholic Church.

It would take a Royal Commission, years of therapy as well as the love and support from her family before she could even begin to heal.

Mrs Isaacs, pictured giving evidence during the Royal Commission into Institutional Responses to Child Sexual Abuse, in 2013 said the church tried to silence her. Picture: Sam MooySource:News Corp Australia

The Brisbane mother-of-two grown up sons has written a tell-all book detailing the abuse and grooming she experienced as well as the attempts of the powerful church to silence her.

To Prey and To Silence is the book she said she had to write, not just for herself but for all victims of sexual abuse who don’t have a voice.

She also wanted it to serve as a warning of the dangers of grooming and how it often goes unnoticed until it’s too late.

Her own abuse, which began when she was just 14, almost destroyed her, leaving a trail of shame — something she carried with her for years.

Joan in 1967 aged just 14.Source:Supplied

Derriman was a priest of the Archdiocese of Brisbane and chaplain of Brisbane’s Sacred Heart Sandgate in 1967 and 1968 when he began grooming her for sex, Mrs Isaacs told the Royal Commission.

Few people knew her secret aside from her mother and now husband, who she had confided in about the abuse as a teenager years earlier.

While her mother believed her and fought to protect her, the church ignored her and swept the problem “under the rug” not even informing her family that her abuser had been moved.

It was something she herself tried to forget until one day she noticed a young girl, around 18 or 20, holding a baby with a much older man on a beach near Brisbane.

“For some reason they caught my eye,” she told news.com.au

Father Derriman was someone who Joan trusted.Source:Supplied

“I thought the old man was her grandfather but then I realised their body language was telling me otherwise.”

To her horror, the man was the same who had abused her all those years ago.

It would be another six months before she had the strength to go to police but then she thought justice was near.

She was wrong, her fight for the truth was just starting.

It wasn’t until 1998 that Derriman was convicted of indecently assaulting Mrs Isaacs and sentenced to one year behind bars, to be suspended after four months.

Joan, pictured with her husband Ian and two young sons in 1978.Source:Supplied

While it was far from long enough Mrs Isaacs said it meant “he could feel powerless”, just as his victims once had.

She thought the battle was over but she reluctantly signed a confidentiality clause in 2001 which meant she couldn’t speak to anyone, except for medical reasons, about her abuse.

In 2013, the church lifted the legally binding agreement in return for a $30,000 payment to Mrs Isaacs, which she said was by now “too little, too late.”

The now retired teacher appeared before the commission’s hearings into Towards Healing — the Church’s internal procedures for dealing with sex abuse. She revealed the institutionalised responses to child sex abuse and how the priest who abused her ran a cult-like group.

Senior prosecutor Sal Vasta, pictured with Joan Isaacs and detective senior constable Derek Kordick who all helped in her fight for justice.Source:Supplied

She said he gave a group of young girls the surname Brown from the Peanuts comic, to make them feel special.

When she threatened to tell what happened or didn’t have sex with him he would threaten to kill himself and ask her whether she could live with that on her conscience.

“The details in my book are just soul destroying,” she said, adding the church which had preached compassion had shown her none.

“I hope my book helps people and I hope it gives parents insight.

“Child abusers aren’t just those who hide behind the bush, they just don’t groom kids, they groom the whole family.”

Francis Edward Derriman, pictured in 1998, was jailed for his crime against Joan.Source:News Limited