The UK’s most prolific catfish ran a “paedophile enterprise” targeting 3,500 children in 30 countries, a court heard.
Alexander McCartney was jailed for life and ordered to serve a minimum of 20 years after posing as a teenage girl to befriend young girls on Snapchat before blackmailing them.
The 26-year-old “stole childhoods” and “shocked communities around the world” with his depravity, police said.
He carried out the abuse on social media on an “industrial scale” and traumatised one girl so much that she committed suicide.
Twelve-year-old Cimarron Thomas, from West Virginia in the US, took her own life in May 2018 after McCartney demanded she involve her younger sister in sex acts and send him pictures.
Her father, Ben, killed himself 18 months later. He died never knowing what caused his daughter to end her life.
In total, McCartney admitted 185 charges against at least 70 children. He also pleaded guilty to the manslaughter of Cimarron.
Prosecutors said they believed it was the first time any abuser in the world had been held accountable for manslaughter, despite never meeting their victim in person.
Sentencing McCartney at Belfast Crown Court on Friday, Mr Justice O’Hara said he had used “social media on an industrial scale to inflict terrible and catastrophic damage on young girls up to and including the death of a 12-year-old”.
He added: “The defendant was remorseless. He ignored multiple opportunities to stop. He ignored multiple pleas for mercy. He lied and lied and then lied again.
“It is truly difficult to think of a sexual deviant who poses a greater risk than this defendant.”
Catherine Kierans, acting head of the Northern Ireland Public Prosecution Service’s Serious Crime Unit, said it was one of the “most distressing and prolific cases of child sexual abuse”.
Victims were identified all over the world, including in Australia, New Zealand and the US.
Former computer science student McCartney, from Newry, Northern Ireland, carried out his offending from the bedroom of his childhood home.
One senior investigator described McCartney’s offending as a “paedophile enterprise” and said he may have targeted 3,500 children from around the world.
McCartney also admitted 59 counts of blackmail, dozens of charges related to making and distributing indecent photographs, and scores of charges of inciting children to engage in sexual activity.
The court heard McCartney first contacted Cimarron four days before her death and blackmailed her into sending images.
After that first night, she believed the ordeal was over, but he contacted her again on May 10.
The Police Service of Northern Ireland (PSNI) recovered the distressing online conversation between the two.
In it, Cimarron repeatedly asked McCartney to leave her alone while he coerced her into sending further pictures. At one point she told him: “I don’t like this.”
When she said she would call the police, he responded “IDC” (I don’t care).
Belfast Crown Court heard that a PSNI officer who reviewed the material said Cimarron was “utterly distraught and sobbing at the time”.
McCartney then demanded she send pictures of her nine-year-old sister. She replied: “Please, not her.”
When Cimarron continued to refuse McCartney’s demands, he began a countdown of 30 seconds before he threatened to post pictures of her online.
He told her: “I am posting, bye. Ben Thomas first (Cimarron’s father). He should see the pix first.”
Cimarron responded: “No, I will obey.”
The conversation then stopped. Three minutes later, Cimarron’s younger sister found her body lying on the floor of her parents’ bedroom.
McCartney first became known to police in Northern Ireland in 2016 when he was arrested in relation to indecent images of children found on his electronic devices.
At this stage, no victims had been identified and he was bailed. He was arrested again on similar offences in 2018.
Despite the attention of police and bail conditions, McCartney continued to offend. He replaced phones and laptops which had been seized.
In March 2019, Police Scotland contacted the PSNI in relation to a report of a 13-year-old girl who was being groomed by an adult suspect believed to be residing in Northern Ireland.
When police raided his home, he was in the middle of offending and Snapchat was open on one of his phones.
Devices seized from his bedroom were found to contain hundreds of thousands of indecent photographs and videos of underage girls.
He targeted young girls who were vulnerable or professing doubts about their sexual identity and body image. He would use this vulnerability to persuade them to send a photo.
Once he had the image, McCartney would go to the notes section of his phone where he had a pre-prepared statement which he would cut and paste into the conversation.
The message would say: “Alright, I used a fake camera snap app. I have your face pic and nudes. You are gonna do as I say for tonight and then I’ll leave after. But if you don’t then I’m uploading everything online for everyone to see. understand?”
Although McCartney promised to leave the victims alone after one night, he often returned later to continue the abuse.
He would blackmail them into sending more images or engaging in sexual activity online, threatening to share the images with other paedophiles.
He forced some children into abusing younger siblings or forced them to involve family pets and objects.
Detective Chief Superintendent Eamonn Corrigan of the PSNI said that McCartney began “offending as a late teenager” from his childhood bedroom.
He had a number of devices and was operating across different time zones.
“McCartney is nothing but a disgusting child predator who was posing as young girls online to groom, manipulate and sexually abuse his victims, as young as four, to satisfy his own sexual perversions and that of other online child sexual offenders.”
Derek Gordon, the special agent in charge of Homeland Security Investigations based in Washington DC, said: “McCartney committed some horrific and disturbing crimes and deserves every minute he serves in prison.
“His wretched conduct tragically led to a child in West Virginia taking her own life.
“We are thankful that our law enforcement partners in Northern Ireland saw fit to apprehend and charge McCartney for his role in the girl’s death.
“Their investigation and prosecution of this case were nothing short of brilliant.”
