After Sascha Chandler's first child was born, he decided to do all he could to bring a paedophile who had abused him more than 15 years earlier to justice.

That decision prompted a remarkable hunt for one of Australia's most notorious paedophiles, Andrew McIntosh.

In an exclusive interview with Australian Story, Mr Chandler reveals the obstacles he faced bringing his abuser to justice.

McIntosh was on parole for child sex offences committed in Grafton, NSW, when he started as a volunteer cadet organiser at one of Sydney's most prestigious private schools, Barker College, in 1990.

He quickly zeroed in on a then 14-year-old Sascha Chandler, following a pattern he had used before and would use again to groom his victims.

First he won Sascha Chandler's trust, then he befriended the family. When the grooming was complete, the abuse began. And it did not stop until Sascha Chandler was 17.

Sascha Chandler tried to move on from his past by moving to London, where he developed a stellar career as a banker.

But when his first child was born, Mr Chandler felt the need to face his demons.

On returning to Australia, he walked into Hornsby Police Station to make a statement.

"Telling the nature of the abuse in front of strangers was a difficult thing to do. Are they going to believe me?" Mr Chandler says.

By 2007, police had gathered enough evidence to arrest McIntosh but there was no trace of him.

Two families sailing their yachts in the Whitsundays had come across a friendly sailor who called himself Hayden Stuart. He seemed to pay an awful lot of attention to their children but was uncomfortable around adults.

Paedophile Andrew McIntosh: Convicted of 24 offences.

They came across documents that revealed the man's real name was Andrew McIntosh, and when they typed his name into a search engine, they discovered he was a wanted paedophile.

McIntosh was arrested but skipped bail not long before his trial was to begin.

Coincidentally, within a few days, one of the families he had sailed with in the Whitsundays spotted McIntosh at the marina in Mooloolaba on Queensland's Sunshine Coast.

They called police but McIntosh got away again.

"It was almost calamitous, the way events were unfolding," recalls detective Andrew Fraser.

"I can't put it into words how livid I was."

In another remarkable coincidence, McIntosh was spotted again by the same family three days later and captured.

The trial went ahead and McIntosh was convicted of 24 offences against Mr Chandler.

Mr Chandler went out of his way to ensure his story would be told publicly, asking the judge in the case to lift the suppression order on his name, something which usually applies in cases of sexual abuse.

He wants to tell his story publicly in the hope that other victims of child abuse might be encouraged to seek justice.

"We had a lot of people telling us not to do it," he says.

"And I said, 'well, I can't sleep at night if I can't stand up as an adult and do my very best to stop this man'."

Despite the dramatic events that led up to the trial and the emotional toll of giving evidence in court, Mr Chandler tells Australian Story the process was "absolutely" worth it.

"It allows me to truly look forward and get on with my life, knowing that he can't hurt anybody else," he says.

Andrew McIntosh is due to be sentenced in August.

Watch the full report on Australian Story tonight at 8pm on ABC1.