By james art Alexander McCartney, 26, admitted 185 charges involving 70 children, although the court was previously told the real number of victims was much higher.
McCartney, who posed as a young girl to befriend other girls on Snapchat before blackmailing them, is believed to be the UK’s most prolific catfish offender, with victims identified around the world.
Twelve-year-old Cimarron Thomas from West Virginia in the US took her own life in May 2018 rather than comply with McCartney’s demands to engage her younger sister in sexual acts.
Eighteen months later, her heartbroken father, Ben Thomas, also killed himself.
McCartney pleaded guilty to manslaughter in connection with Cimarron’s death.
He also admitted 59 charges of extortion, dozens of charges related to making and distributing indecent photographs and dozens of charges of inciting children to perform sexual acts.
The crimes spanned a period from 2014 to 2019, with victims identified around the world, including Australia, New Zealand and the United States.
McCartney used his technical knowledge as a computer science student to commit his crimes.
His crime was committed from the bedroom of his childhood home.
McCartney, originally from Lissummon Road outside Newry, has been held in Maghaberry Prison since 2019.
He posed on social media platform Snapchat as a teenage girl and befriended vulnerable girls aged between 10 and 16 who were gay or exploring their sexuality.
After securing a photo from his victims, he reveals a “catfish” and blackmails them into engaging in sexual acts.
In some cases, he required his victims to include younger siblings.
McCartney told one girl that he would have people come to her house to rape her if she did not comply with his demands.
McCartney was arrested several times between 2016 and 2019, but continued to commit crimes despite his bail conditions until he was remanded in custody.
At a pre-sentence hearing last week, a prosecution lawyer said McCartney humiliated and humiliated his victims, saying the harm he caused them was “immeasurable”.
The attorney also read portions of a victim impact statement provided to the court by Cimarron Thomas’ grandparents.
The statement said: “Our lives will never be the same.
“We didn’t get to see her graduate, walk down the aisle, or have children.
“We were robbed of those memories. Our lives changed forever.
Judge O’Hara will sentence McCartney on Friday at Belfast Crown Court.