Image source, Family handout

We're about to end our live page coverage of the sentencing of Alexander McCartney, one of the UK's most prolific child abusers.

He's been sentenced to life in prison and must serve a minimum of 20 years.

We want to leave you with these two photographs of Cimarron Thomas and her father Ben.

Cimarron, from West Virginia, USA, played the violin, she loved elephants and chatting with her friends.

Her grandfather Dale sent us this photo of her and it's how he wants her to be remembered.

Ben, a former US Army veteran, took his own life without knowing what McCartney had put Cimarron through.

If you are victim of online abuse, please contact your local police force.

If you you have been impacted by the coverage today please visit the BBC Action Line.

This live page was edited by Matt Fox and Peter Coulter, with live court reporting from Luke Sproule. The page was written by Abigail Taylor, Catherine Moore, Adam Mandeville, Emily McGarvey and Marita Moloney.

Image source, Dale Thomas

Image source, PSNI

We'll be finishing our live coverage of this story shortly.

For those of you just joining us, here's a recap of today's events:

• Alexander McCartney was sentenced to life with a minimum of 20 years in prison with a minimum term of 20 years after admitting to the manslaughter of a 12-year-old girl and the extreme sexual exploitation of other young girl
• The court heard that after being abused by McCartney, 12-year-old Cimarron Thomas, from West Virginia, told him she was going to kill herself, to which he replied “good luck and goodbye”
• Cimarron took her own life rather than comply with McCartney’s depraved demands that she include her younger sister in the abuse
• Cimarron's grandparents, Peggy and Dale Thomas, spoke of their heartbreak, "Our lives will never be the same again," they said
• Catherine Kierans, acting head of the PPS Serious Crime Unit, described the McCartney case as one of the most "depraved, distressing and prolific cases of child sexual abuse that we have ever seen"
• Detectives describe McCartney as a “disgusting child predator”
• Det Ch Supt Corrigan said that McCartney’s crimes were to “satisfy his own sexual perversions and that of other online child sexual offenders"
• He said McCartney has caused “serious and long-lasting harm on what we estimate to be around 3,500 victims and their families"
• The US Department of Homeland Security said McCartney "deserves every minute he serves in prison”

Read more on this story here.

The Police Service of Northern Ireland is making an appeal to all parents and guardians of young people to be vigilant and check in on who they may be talking to online.

They have published advice on their website, external.

Parents, guardians and wider local communities should report any activity, online or physical towards a child that they find concerning, police say.

Similarly, if you have concerns or suspicions that an adult you know or live with may be engaging in this type of illegal activity, report to Police on 101 or 999 in an emergency.

If you have been affected by any of the details on this live page, you can visit BBC Action Line

Many of McCartney's child victims have never been identified but all their lives have been changed forever with unimaginable consequences.

But the family of 12-year-old Cimarron Thomas, who was abused by McCartney, have been left heartbroken after she killed herself, when he demanded she include her younger sister in the abuse.

BBC News NI has also been speaking to a man in New Zealand who revealed the devastation caused to his eldest daughter by McCartney's depravity.

Read more on this story here.

Image source, Cimarron Thomas memorial Facebook page

It was a phone call from a 13-year-old girl to police in Scotland in 2019 that eventually led to the capture of Alexander McCartney.

Police then spoke to more children during the investigation.

Senior prosecutor Catherine Kierans paid tribute to those children "Their courage stands in stark contrast to his cowardice in targeting vulnerable young girls," she said.

Image source, Getty Images

Let us remind you of some of Mr Justice O’Hara's most damning remarks from Belfast Crown Court this afternoon.

Speaking ahead of delivering his sentence, the judge said the details of McCartney's offending put the case “on a par with murder” .

He described them as crimes of “sadism and depravity”.

McCartney found ways to “degrade and humiliate” his victims and he wanted to see how hard he could push his victims and how far he could control them, he added.

McCartney was “absolutely devoid of empathy or remorse at the time” and used social media on "an industrial scale", he added.

The court heard details about the abuse suffered by 12-year-old Cimarron Thomas, who shot herself after being catfished by McCartney.

Belfast Crown Court heard that when she told McCartney she was going to kill herself, he replied “good luck and goodbye”.

In his closing remarks, Mr Justice O'Hara said it is hard to think of “a sexual deviant who poses more risk than this defendant”

The judge imposed a life sentence on McCartney with a tariff of a minimum of 20 years.

He added that he did not envy the parole board who would have to assess whether McCartney would be eligible for release - which will not be until at least 2039.

Victim Support NI has stressed the importance of communication that parents have with children.

In a statement, the organisation said: "Alexander McCartney is just one individual, who caused the death of one 12-year-old and unthinkable harm to thousands of young victims, many of whom were too embarrassed or ashamed to ask their parents or guardians for help.

"Tell kids in your care that they can always come to you if they are being threatened or blackmailed online."

The “real feature” of this case was the “complete cowardice” of McCartney targeting young, vulnerable children, says Catherine Kierans, from the Public Prosecution Service.

“We were absolutely determined to bring him to justice,” she tells BBC News NI.

“The bravery of the victims was just an inspiration to us.”

Some further examples of conversations McCartney had, released by police earlier.

McCartney befriended the children while pretending to be the same age as them, often using past images of his victims to groom other victims.

More now from the father of two of McCartney’s victims from New Zealand.

His daughters, aged 12 and 10, were contacted by McCartney online in December 2017, who then coerced his eldest daughter and took intimate images of her, using them then to blackmail.

In a statement issued by the Police Service of Northern Ireland, he said: “As parents you do your best to shield and protect your children from the monsters of the world, only to find out too late the dangers of the internet are all too real and that you weren't vigilant enough.

“Having both of our daughters involved is gut-wrenching. Within the four walls of our home they should be safe, and he manipulated and preyed on their innocence for his own sick enjoyment.”

McCartney's offending has had a "profound impact" on his eldest daughter, he told BBC News NI.

At the beginning of the year, she moved away for university but moved home after six weeks.

"I believe she missed out on opportunities because of trust issues. It's something she's going to deal with forever," he said.

"We know she's on this medication all the time, and the dark places that I'm sure her mind goes when she's alone."

Image source, NurPhoto (Getty Images)

Police believe that Alexander McCartney targeted around 3,500 children in more than 30 countries around the world.

He had 64 devices that he was using to contact his victims.

Prosecutors said he was offending so frequently that it was hard to know how he had time to do anything else.

He messaged so many children that he even copied and pasted his messages to them to save time.

Police were able to track some of his victims down as he had kept screenshots of their Snapchat location pins.

When police turned up at the door it was often the first time they had told their parents what had been happening to them.

The litany of McCartney's crimes spanned continents.

BBC News NI has spoken to a man from New Zealand, we've called him Stephen (not his real name), about the abuse suffered by his two girls, after McCartney struck up a friendship with his eldest daughter, then 12, on Snapchat.

The girl, we've called her Rebecca (not her real name), believed that she was talking to another girl, and had no idea it was McCartney.

The friendship grew over a period of a few months.

Then McCartney asked Rebecca for a nude photograph, which she sent.

"He then used that to manipulate and blackmail her into sending more photos, which ended up including our youngest daughter as well as part of the blackmail," Stephen said.

"And then, in time, through her contact list on Snapchat he added Rebecca's cousin as well, who was older at the time, and he then tried to threaten her with getting more photos.

"Thankfully, she was mature enough and smart enough to reach out to my wife, and then we went straight to the police from there."

Read more on this here.

Image source, Getty Images

Detective Chief Superintendent Eamonn Corrigan was speaking outside Belfast Crown Court earlier this afternoon.

McCartney was "relentless and cruel", he told reporters.

"His offending has shocked communities around the world."

Image source, Dale Thomas

Twelve-year-old Cimarron Thomas took her own life after being abused by Alexander McCartney.

Her family didn't know what she had been going through, she hadn't told them as McCartney was threatening to publish her pictures online.

Her father Ben, a US Army veteran, really struggled and 18 months later he took his own life as well.

Ben died not knowing what Cimarron had been through or the abuse she had suffered.

It was only during the Police Service of Northern Ireland's investigation that they found photos and conversations that she had with McCartney.

They were then able to reveal the truth to the family.

Image source, IWF

The Internet Watch Foundation (IWF) says it is the UK's "frontline" against the spread of child sex abuse imagery.

It's interim chief executive, Derek Ray-Hill, describes the damage done by McCartney as "incalculable".

"His offences remind us this sort of abuse costs young lives. And the Child Sexual Abuse Material may linger online to haunt his victims over and over again until it is finally removed," he says in a statement.

“Over the last decade, the IWF has seen offences like this skyrocket.

"Offenders like McCartney can now contact children and force them into the most appalling sexual abuse – all without needing to ever be in the same room.

"The internet is an open door to our children’s bedrooms through which criminals like McCartney can gain access."

He adds that if children find themselves being approached and manipulated, "I want them to know it is never their fault, and they are not alone".

If you have been affected by any of the content on this live page, you can visit BBC Action Line.

McCartney had thousands of victims right across the world.

BBC News NI has spoken to a man from New Zealand, about the abuse suffered by his two girls, after McCartney struck up a friendship with his eldest daughter, then 12, on Snapchat.

She believed that she was talking to another girl, and a friendship grew.

Then McCartney asked her for a nude photograph, which she sent.

"He then used that to manipulate and blackmail her into sending more photos, which ended up including our youngest daughter as well as part of the blackmail," said the dad.

He said as soon as the first photo was sent, McCartney had power, and his daughter was "playing by his rules" adding: "He preyed on her innocence."

Between January 2021 and March 2024 Alexander McCartney pleaded guilty to:

• One count of manslaughter
• 14 counts of causing or inciting a girl under 13 to engage in sexual activity involving penetration
• 32 counts of causing or inciting a girl between the age of 13 and 16 to engage in sexual activity involving penetration
• Nine counts of causing a girl under 13 years of age to engage in sexual activity
• 14 counts of causing a girl aged between 13 and 16 to engage in sexual activity
• 58 counts of blackmail
• 29 counts of making indecent images of children
• 11 counts of distributing in indecent images of children
• Two counts of causing a person to engage in sexual activity without consent
• 12 counts of possessing indecent images of children
• One count of intimidation
• One count of possessing prohibited images of children
• One count of sexual communication with a child

A child abuse lawyer has called for the Online Safety Act to go further into the realms of preventing contact from adults "masquerading" as children.

David Greenwood spoke a little earlier to our colleagues on the news channel.

The Online Safety Act is due to come into force next year after becoming law last year.

It will require social media platforms to protect children from certain types of content and also creates new offences including of cyber-flashing.

The Act applies to the United Kingdom as a whole - with the exception of certain provisions.

Greenwood calls it "a great start" but adds that the law should eventually go further to prevent "this kind of contact from outsiders into a child's phone or computer altogether".

"It will need careful use of technology but I think this can be done," he adds as he suggests it should be a consideration for those in charge of the Online Safety Act and proposed guidance.

Speaking earlier, Ms Kierans described the McCartney case as one of the most "depraved, distressing and prolific cases of child sexual abuse that we have ever seen".

Image source, Facebook

McCartney first came to the police’s attention when he was a teenager due to his online activity.

It was a phone call from a 13-year-old girl in Scotland in 2019 that eventually led to his capture.

During an unsuccessful bail application earlier in the case, the court heard that McCartney said he would upload an image of the girl from Scotland to the internet if she did not do what he asked.

Over the next three years searches were conducted and devices seized on four occasions.

As these devices were studied, the severity of McCartney’s offending was laid bare.

The investigation spread across the globe to countries such as Australia, New Zealand and the United States as well as the UK and Republic of Ireland.

Earlier, Mr Justice O'Hara said the details of McCartney's offending put the case “on a par with murder” .

He added that he did not envy the parole board who would have to assess whether McCartney would be eligible for release - which will not be until at least 2039.