Underage online sexual exploitation, Northern Ireland college students sentenced to life in prison... "3,500 victims."

A college student in his 20s was sentenced to life in prison for threatening and sexually exploiting female children he met online.

A court in Northern Ireland sentenced 26-year-old Alexander McCartney, a computer engineering college student, to life in prison for sexually exploiting 70 girls around the world, including Britain, the United States and Australia.

McCartney is accused of pretending to be a female student of his age through Snapchat or Instagram, and then encouraging him to send her body exposure photos or sexual videos after getting close to her.

When McCartney received a photo or video, he shared it online and used it to intimidate victims, the investigation found.

In 2018, a 12-year-old American victim killed himself, and his father followed.

Police say a 3-year-old toddler was among those McCartney threatened victims into sexual exploitation.

At trial, McCartney admitted all charges.

There are 70 victims listed in the indictment, but police believe the number of victims is about 3,500 in 30 countries.