A 51-year-old Queensland man was one of the state's worst online sexual offenders by night, and a tax office employee by day, a court has heard.
Jason Tanira Kerr was having up to 18 drinks a night while grooming children and getting them to perform sexual acts online for about five years until his arrest in 2019.
He was a "high-functioning" alcoholic working for the Australian Tax Office until he was made redundant in 2016, but obtained other employment, a court was told.
Kerr pleaded guilty to more than 100 charges in the Brisbane District Court on Wednesday.
Police searched his house in January 2019 after Kerr communicated online with an undercover officer pretending to be a 14-year-old girl.
Kerr claimed to be a boy of the same age.
Officers found more than 500 pictures and 126 videos containing child exploitation material.
This included screenshots of chat-logs and recordings of Skype conversations with 97 users who identified themselves as children.
At least 19 were confirmed to be underage from footage, but the Crown argued the vast majority would have been children.
Kerr asked the children to perform sexualised acts, in one case sending a video of a 14-year-old to another boy as "an example of what he liked".
His offending was "horrifically persistent" and he is a high risk to the community, crown prosecutor Toby Corsbie told the court.
"This offender is ... someone from whom the community and the community's children need to be protected," he said.
"From my analysis, which I don't claim to be exhaustive, but based on it, he is one of the worst internet-based sexual offenders in Queensland's history."
Kerr pleaded guilty to 111 charges - including 54 counts of using the internet to procure children under the age of 16 and 44 counts of grooming children.
The court heard he was convicted in 2013 of similar offences relating to a 15-year-old boy and a 13-year-old girl.
He was given a wholly suspended sentence because he was regarded as at low-risk of reoffending.
Kerr was living with his parents when first on probation after that conviction, but "things fell apart" when they moved to the Sunshine Coast and he went to live alone, his barrister Penny White told the court.
"On my instructions, he just fell back into that pattern of abusing alcohol," she said.
Kerr was drinking up to 18 alcoholic drinks a night but was "clearly a high functioning alcoholic" because he worked in the day.
"And it was while he was under the influence of alcohol that this offending occurred," Ms White said.
She told the court he was extremely ashamed and embarrased about his behaviour.
Judge Gary Long has reserved his decision.