A serial sexual predator who used Snapchat to prey on more than 100 children was jailed by a Finnish court Thursday.

Most of the 120 underage girls who brought charges against Jesse Erkkonen were aged between 12 and 16.

The court in Pirkanmaa in southern Finland heard the 27-year-old used the social media platform to approach young girls, asking them for naked photos and sexual videos.

It sentenced him to 10 years and a half years in prison for 20 counts of aggravated child sexual abuse, 59 counts of child sexual abuse, as well as other charges including blackmail, threats and cannabis-related offences. Erkkonen faced 190 charges in all.

Most of the victims were from the town of Valkeakoski and surrounding areas.

Erkkonen persuaded some of his victims to meet up and engage in sexual activity, promising them money, alcohol, tobacco or cannabis and then threatened to spread his victims' pictures.

In one case, Erkkonen asked an 11-year-old girl to film her seven-year-old sister and her friend while they were naked in the shower.

"Some of the plaintiffs told that Erkkonen had asked their age and once they said they were under the age of consent, Erkkonen had said that it did not bother him," the court ruling said. 

Erkkonen denied most of the charges, saying he could not remember.

The cases came to light in 2021 when 10 of the victims told their school counsellor about what had happened.

Erkkonen has been in custody since 2021.