A “relentless and cruel” online predator who blackmailed girls around the world was jailed for at least 20 years on Friday after being convicted of the manslaughter of a victim who took her own life.

Prosecutors say Alexander McCartney, 26, of Newry, in Northern Irelandpretended to be a teenage girl and carried out catfishing attacks on 3,500 female victims he contacted on platforms including Snapchat.

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Catfishing uses a fake online identity to trick victims. Authorities said McCartney encouraged his victims to send intimate photos or engage in sexual acts, then extorted them by threatening to share the images.

A 12-year-old child in West Virginia committed suicide in May 2018 during an online conversation with McCartney, while McCartney was demanding sex. The victim’s father committed suicide 18 months later.

Detective Chief Superintendent Eamonn Corrigan, Police Service of Northern Ireland and Catherine Kierans, Public Prosecution Service of NI, speak to the media outside Belfast Crown Court after prolific online predator Alexander McCartney was sentenced to at least 20 years prison after admitting 185 charges involving 70 children. Friday. (Brian Lawless/PA via AP)

Prosecutors said they believe this is the first time someone has been convicted of manslaughter in a case where the victim and perpetrator never met.

“Working closely with the police, the prosecution team was able to establish to the criminal standard that McCartney’s actions caused the girl’s death and he had a case to answer for manslaughter,” Acting Chief Constable Catherine Kieran said. Prosecutions in Northern Ireland. Serious Crime Unit.

Police have identified victims in 30 countries, including AustraliaNew Zealand and the United States.

McCartney, who committed his crimes from the bedroom of his childhood home, pleaded guilty to 185 charges involving 70 children, including manslaughter. At Belfast Crown Court, Judge John O’Hara sentenced him to life without the possibility of parole for 20 years.

“To my knowledge, there has not been a case like the present where a defendant has used social media on an industrial scale to cause such terrible and catastrophic damage,” the judge said.

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Detective Chief Constable Eamonn Corrigan of the Police Service of Northern Ireland said outside court that McCartney was a “relentless and cruel” pedophile.

“We cannot underestimate the devastation he caused and the childhoods he stole,” the officer said. “There was nothing to stop him except to put him in jail.”