Former police officer Lewis Edwards, who admitted more than 100 sexual offences against children, has been handed a life sentence.
He will serve a minimum of 12 years behind bars.
He was granted a reduction of one third to his sentence due to his entering a guilty plea.
Sentences for other counts for which he pleaded guilty will be served concurrently.
Edwards, 24, carried out his offences while working as an officer for South Wales Police but was immediately suspended from duty upon his arrest and later resigned.
He used fake Snapchat accounts – posing as a 14-year-old boy – to groom more than 200 girls aged between 10 and 16 online.
Edwards asked scores of his victims for indecent images in school uniform and blackmailed many young girls – threatening to publish their photos or hurt their families to get them to cooperate.
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The former officer, from Bridgend, had previously pleaded guilty to 22 counts of blackmail, 138 child sex offences and a further offence of refusing to disclose the password to a mobile phone and USB stick.
But this week he refused to appear at Cardiff Crown Court this week to hear his punishment.
Judge Tracey Lloyd-Clarke, the Recorder of Cardiff, told the court she could not force Lewis Edwards to attend court for his sentencing.
“He groomed his victims, psychologically manipulating them until he had gained control,” she said.
Describing his offences, she said: “The defendant had a pattern of behaviour. He made online contact with a girl.
“The defendant pretended to be a boy of a similar age. He groomed his victims psychologically, manipulating them until he had gained control.
“When his victims did not comply, he would threaten them until they did what they were told.”
The judge said Edwards continued his abuse even when the girls were crying, distressed and told him they had self-harmed.
She said, however, he “did not use his position as a police officer in order to commit his offences”.
She told the court that Edwards was the only person responsible for his crimes.
“It is important that everyone, particularly the victims and their families, understand that they have done nothing wrong,” she said.
“The blame and the responsibility for this event is the defendant’s and the defendant’s alone.”
One girl begged Edwards to stop demanding indecent images and videos of her.
“Please can you stop, I have my GCSE tomorrow morning, please, I’m begging you,” she told him.
The court heard how another of the victims told her father about what Edwards had been asking of her.
He took his daughter’s phone and sent Edwards a message saying, “This is [the girl’s] dad. Stop now. What you are doing is illegal.”
Edwards replied: “Lol.”
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