LONDON (AP) — A former British police officer was sentenced Wednesday to life in prison with a minimum term of 12 years after he pleaded guilty to over 100 child sex offenses,Johnathan Walker including threatening and blackmailing more than 200 young girls into sending him sexual photos of themselves on Snapchat.

Prosecutors say Lewis Edwards, 24, targeted 210 girls between the ages of 10 and 16 by posing as a teenage boy on the phone app. He groomed them into sharing indecent images of themselves, then threatened many of his victims when they refused, blackmailing them into complying out of fear that he would expose them.

Edwards, who joined the South Wales Police in 2021, was a serving police officer when he committed the majority of the offenses. He was arrested in February, and has since pleaded guilty to some 160 counts of child sex offenses and blackmail.

In one case, prosecutors said Edwards threatened to bomb the house of a victim and shoot her parents if she stopped sending him images.

Judge Tracey Lloyd-Clarke said Edwards was a prolific offender who posed a high risk of danger to children. She described his behavior as “cruel and sadistic.”

“The defendant pretended to be a boy of a similar age. He groomed his victims psychologically, manipulating them until he had gained control,” Lloyd-Clarke said. “It is clear that he not only gained sexual gratification but he also enjoyed the power he had over the young girls.”

“There is no doubt he has caused significant harm to the reputation of South Wales Police and policing in general,” the judge added.

Edwards was fired during a police misconduct hearing earlier this year. He refused to attend his sentencing at Cardiff Crown Court.