A teacher who told a 17-year-old student to wear a skirt to school so they could have sex in a classroom first taught the girl when she was just 13.
But despite being the girl’s mentor for three years and repeatedly having sex with her at his home, Gavin Malcolm Duncan still denies he groomed the child.
Duncan was jailed last week for seven months but the girl, now 19, will have to live with how he took advantage of her vulnerability for the rest of her life.
Daily Mail Australia can reveal the full details of how Duncan, a popular teacher and rugby player, met and befriended the girl then betrayed her trust over five years.
Duncan was 26 when he was employed as a maths teacher at Katoomba High School in the Blue Mountains, west of Sydney, in 2014. The girl was 13 and in Year 8.
Teacher Gavin Malcolm Duncan (pictured) told a 17-year-old student to wear a skirt to school so they could have sex in a classroom. He first taught the girl when she was just 13
Duncan was 26 when he was employed as a maths teacher at Katoomba High School (pictured) in the Blue Mountains, west of Sydney, in 2014. He later became her mentor
From 2016 to 2018 when the girl graduated Duncan was her mentor, providing her with guidance on school and outside issues, including her personal relationships.
The girl would attend Duncan’s classroom for private conversations and their conversations became flirtatious over time.
In December 2017, when Duncan was 30 and the girl 17, he gave her his mobile phone number and they began communicating by text message during and after school.
Six months later, in June 2018, the girl was shopping at Westfield Penrith when the pair arranged to meet in a series of text messages.
Duncan took an Uber to the shopping centre, picked up the girl and they went to his home at nearby Glenmore Park. Once there, he took her straight to his bedroom.
According to a statement of facts tendered to court, Duncan asked the girl if anyone knew she was at his home.
‘No,’ she replied. ‘They think I am on the train and I have turned off my Snapchat maps.’
The pair sat on his bed and while they were kissing he took off her clothes, then his own. She performed a sex act on him before they had intercourse.
According to the statement of facts Duncan then paid for an Uber to take the girl to the train station so she could go home.
Despite being the girl’s mentor for three years and repeatedly having sex with her at his home, Gavin Malcolm Duncan (pictured) still denies he groomed the child
The schoolgirl was shopping at Westfield Penrith (pictured) when she exchanged a series of text messages with Duncan. He picked her up in an Uber and took her to his home for sex
‘As she was leaving in the Uber he told her to wear a skirt to school the next day so he could f*** her in the classroom,’ the statement of facts said.
Two weeks later Duncan and the girl separately attended State of Origin II at ANZ Stadium and exchanged flirty text messages during the game.
He sent her his address and she drove to his house. They had sex the same way as on the first occasion, before the girl drove herself home.
He told her to wear a skirt to school the next day so he could f*** her in the classroom
A week later the girl sent Duncan a text message to say she was in the Penrith area and to ask what he was doing. He told her to drive to his house and the sex scenario played out again.
While they were having intercourse Duncan said to the girl: ‘Everything about this is so wrong, but this feels so f***king good.’
In the days after the third sexual encounter Duncan and the victim had a discussion at school about what had been going on between them.
He said to her: ‘We shouldn’t do this. You may have feelings for me and then get the s***s with me and go and tell someone about this.’
Duncan and the schoolgirl exchanged flirty messages when they separately attended game two of the 2018 State of Origin series at ANZ Stadium (pictured). They had sex that night
She replied: ‘No, I won’t. It wouldn’t work between us.’
Duncan continued to have sex with the girl after she turned 18 and graduated from the school.
By mid-May the next year rumours of their sexual relationship were circulating through Katoomba High.
Duncan was a keen sportsman who played for Blue Mountains Rugby Club
Principal Jennifer Boyall spoke to Duncan about the allegations and a report was sent to the New South Wales Department of Education. Duncan then told the girl that Ms Boyall had confronted him.
‘He told her he was surprised it had not come up earlier as the rumours had been going around for ages,’ the statement of facts said.
The girl asked Duncan what she should do and he said: ‘Deny, deny, deny.’
Eight days later the girl told a woman with whom Duncan had previously been in a relationship for several years what had been happening between the pair.
The following day that woman went to police and on June 21 last year Ms Boyall suspended Duncan and had him removed from the school grounds.
Duncan and his former adult partner spoke on the phone 24 hours later and he made ‘full and frank’ disclosures about his relationship with the girl.
In that conversation, which was recorded, Duncan said the sex with the schoolgirl had been ‘opportunistic’, ‘completely random’ and ‘not organised’.
Duncan had sex with the 17-year-old schoolgirl three times in the bedroom of his home at Glenmore Park in western Sydney. He no longer lives at the property (pictured)
He could not explain his actions and denied taking advantage of the girl. ‘It was someone giving me the attention that I craved,’ he claimed.
Duncan was arrested on July 4 and interviewed at Penrith police station where he told detectives of his history with the girl.
He described their relationship as a ‘strong friendship’ that had been building as she grew older. She came to him with problems and trusted him to sort them out for her.
Duncan initially claimed his relationship with the girl had not been physical when she was still at school and they had not had sex until after she turned 18.
Katoomba High School principal Jennifer Boyall (pictured) suspended Duncan and had him removed from the school grounds
He eventually admitted she was 17 when they started having sex but could not remember the encounter after the State of Origin match because he was drunk at the time.
Duncan pleaded guilty in December to three counts of sexual intercourse with a person under special care. Three further counts of the same offence were taken into account upon sentencing.
In a victim impact statement the girl read to Penrith District Court she described how Duncan had groomed her while at school.
‘I felt comfortable opening up and he was always happy to listen to me,’ she said.
‘This made him the best person in my life at the time, because I believed he cared about me.
‘Every choice I made, I would ask myself how Gav would react if he found out and he always knew what I was up to… which I now realise was part of the grooming.
The girl described being ostracised by her school friends since Duncan’s arrest and said she had suffered from anxiety and depression.
‘People told me I’d lived out my fantasy while he had to suffer,’ she said. ‘It was the last I heard from any of my school friends.
‘I’ve been told I wasted my life and should have said no but no one understands what it’s like to be groomed.’
By mid-May last year rumours of Duncan’s sexual relationship with the former student were circulating through Katoomba High School (pictured)
Duncan, now 33, wept while the girl read her statement and said he now understood the harm he had done to her.
He told the court he was not sexually attracted to schoolgirls and was ‘extremely sorry’ for his crimes.
Defence barrister Paul Rowe disputed that his client had groomed the girl and said he had used her ‘as a shoulder to lean on during a very trying time’.
Mr Duncan totally lost his moral compass in circumstances living with the weight of all these problems
Mr Rowe said a psychologist had found Duncan suffered from an undiagnosed persistent complex bereavement disorder after the death of his mother and a cousin.
‘Mr Duncan totally lost his moral compass in circumstances living with the weight of all these problems,’ Mr Rowe said.
Duncan, who played for Blue Mountains Rugby Club, had begun a plumbing apprenticeship and been in a de facto relationship for a year.
Judge Sharon Harris accepted he had shown remorse but said had to go to jail.
‘A school student should expect the teacher has her best interests at heart,’ Judge Harris said.
Last Tuesday Judge Harris sentenced Duncan to 15 months in prison with a non-parole period of seven months. He will be eligible for parole on January 15 next year.