Sleepless nights, overwhelming guilt and a fear-driven urge to hurl warnings at parents putting their kids in out-of-school care.

That is the heart-wrenching result of David William James' child abuse as described by the mother of one of his victims.

The 27-year-old took explicit photos and videos of children younger than 10 while working at six out-of-school centres across Sydney between April 2021 and May 2024.

Australian Federal Police officers closed in on James after linking him to child abuse material on the dark web.

He pleaded guilty to 11 charges related to the production and possession of child abuse material, including doing a sexual act with a child.

Police notified about 1,500 parents of children who attended nearly 60 Sydney childcare centres where James worked casually during the period of offending.

His arrest and long resume, including stints at some of Sydney's most elite private schools, sparked shock and outrage in the community.

Police initially laid 31 charges against James, with 20 withdrawn after his guilty plea.

A victim impact statement written by the mother of one of James' victims was shared during a sentencing hearing on Friday.

'From the moment the AFP contacted me it feels as if my family's world has been irreversibly changed,' she wrote.

'I no longer consider any person or place safe, I struggle to reconcile the idea that my children are safe anywhere that they are not with myself or my husband.'

The woman described herself as racked with guilt, haunted by the event and by the question of whether she could have prevented it.

'Most nights I wake up and think about what happened,' she wrote.

'I will forever wonder whether (my child) was trying to tell me something at the time and that I misread the signs.

'I do not think I will ever be able to escape that guilt or the impact this person has had on our lives.'

She described enduring daily triggers and having to repress an urge to scream when she saw children with care workers.

Dialling into the Downing Centre courtroom from a custody cell, James sat still staring straight ahead as the statement was read.

Having failed probation to become a police officer, he was employed in a civilian capacity at the time he was abusing kids in his care.

NSW Police was unaware of his work in the childcare sector.

During the hearing, lawyers debated the admissibility of notes James wrote to the court alleging he was a victim of abuse.

James claimed he was groomed and abused on dark web chat rooms prior to his offending.

Barrister Jeremy Etkind said his client was forthcoming about his history and sexual interest in children.

'He does give the good, the bad and the ugly,' Mr Etkind said.

'He's said things that are harmful to him, but which show an honesty and an openness in dealing with his conduct.'

James claimed his offences were partly motivated by a need to perform in front of a camera.

'I must say I'm concerned about his own account,' Judge Newton said.

'It's clearly sexual gratification. You couldn't get a starker example.'

James took children into prohibited areas of the childcare centres before taking photos and videos of them.

He is confined to his cell for 23.5 hours a day, and has been ostracised after being identified as working for police.

'You commit these crimes, you get what comes with it,' Judge Newton said.

James will be sentenced on July 2.

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