Former high school teacher and womens' basketball coach Patrick Foley Wilson's online conversation started innocently enough.
"Tell me a funny or embarrassing story haha" he asked the girl, "jess13syd", he'd just met on a chat site. "You got a bf yet beach gal?"
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Meet the cops that protect our kids online
The NSW Police strike force Trawler has arrested almost one person per week this year.
But it didn't take long for "beachloverM" to direct his chat with the 13-year-old to a much darker place.
"Ever go without wearing undies?" the then Canberra Boys Grammar School teacher continued. "Imagine those boys walking up the stairs behind you."
Over four months his conversations with the girl he thought was 13-year-old Jess became increasingly graphic until Wilson's parents received a knock on their Chatswood door in June 2015 to tell them their son had actually been grooming an undercover police officer.
Wilson's mug shot is now one of dozens on the "wall of shame", a chilling spread of offenders' photos adorning the walls of the NSW Police's Child Exploitation Internet Unit in Parramatta.
"It's a reminder of what we're dealing with," said the unit's manager, Detective Inspector Mick Haddow.
Police are increasingly using undercover stings to catch online predators through the unit's Strike Force Trawler, an "exponentially growing" investigation within the Sex Crimes Squad.
The strike force has arrested almost one person per week this year with many more cases passed to local area commands.
The faces on the "wall of shame" are diverse; from teenagers to 70-year-olds, school teachers, fathers, defence force members, priests, police academy students and aspiring politicians.
There is Steve Myhill, an executive TV producer who worked on shows like The Mole and was arrested at the St Leonard's office of Fremantle Media. He has since pleaded guilty and been sacked.
There is ADF member Jason Burton, set to go to trial in 2017. And Greens member Karel Solomon, a candidate in the 2012 Marrickville local council election who will be sentenced next year.
The look on their faces when police knock on their door and reveal they were talking to an officer is just part of the satisfaction that helps them investigate such horrific crimes against children, Mr Haddow said.
"Some people can't understand why you would do this [job] but the reason is because you care for children," he said.
Two computers in the unit's office, incongruously decorated in cheery tinsel, are used by officers to go undercover and slip into the mind of a young girl.
About 70 per cent of cases start with a tip off – usually from parents who have noticed a concerning online conversation and reported it to local police.
The rest are "cold starters" in which officers trawl chat sites, social networks and apps.
"This is not all about fictional children. The majority of matters initially involve a real child and it's only through good parenting, education and sometimes just luck that we get to them," he said.
Transcripts from several cases obtained by Fairfax Media show that the undercover officers don't bait or initiate sexualised talk. It is largely one-sided and often happen disturbingly fast.
In Wilson's case, the young girl on Chat Avenue spoke about school, her pet dog or netball and was innocently ignorant of the sexualised questions he started asking about masturbating or being spanked.
Wilson, 28, later agreed with a District Court judge who called the language he used to relay graphic fantasies "disgusting".
"I felt that the internet was just unreal, that it was a made-up cyber-world in which I could run rampant," he told his sentencing hearing in August.
Wilson was handed a two-year prison sentence to be served as an intensive corrections order in the community and he has been banned from working with children.
He was sacked from Canberra Boys Grammar upon his arrest and there is no evidence he committed offences against students.
He said he had used internet chat rooms since a teen out of loneliness, curiosity and an inability to talk about sex in real life.
He was adamant he had no desire to meet up with jess13syd despite suggesting it several times. After several sessions with a psychiatrist, he accepted he had paedophilic tendencies.
"It's the most shameful episode of my life," he told the court.
The maximum penalty for using a carriage service to groom an underage person for sex – the charge most commonly used in these cases – is 15 years.
But government data shows less than half of offenders receive a prison sentence. Many sentences are shorter than the prison rehabilitation programs.
"The sentences imposed are something that remain a concern to police," Mr Haddow said. "The challenge for us is to get the message across that these are really serious crimes against children."
Last week, another Strike Force Trawler target, Ermington father-of-three Raffi Moskofian, 53, was sentenced to 27 months' jail, of which 12 months is non-parole, for 13 Skype conversations with a fictitious 14-year-old.
He sent her porn images, semi-naked photos of himself and five sexual videos of himself.
The part-time disability school bus driver, who was sacked when he was arrested, blamed the offending on the fact his wife and his mother didn't get on.
"It was always conflict between them and at the time my sister passed away as well and I was kind of lost," he told Parramatta District Court. "I just wanted to lose myself and be somewhere else."
He claimed he had no intention to meet up with the girl but Judge Andrew Colefax saw otherwise.
"Grooming is one step at a time," he said.
He said Mr Moskofian seemed more concerned about the impact of his arrest on him and his family only. "You have daughters of your own," he said. "Have you got any idea of how dangerous and damaging what you did could have been if that person had been 14?"
Police said they can't arrest their way out of the pervasive world of online grooming. Half of their work is about educating parents and children.
"Know who your children are actually speaking to online," Sex Crimes Squad commander Linda Howlett said. "Have safety measures in regards to who they speak to online... [and] remind your children to never meet someone they've met online."
Clarification: This story was updated to clarify that Patrick Foley Wilson is no longer employed by Canberra Boys Grammar School and was suspended and then dismissed immediately after his arrest.