A paedophile who used the internet to blackmail young girls all over the world has been jailed for 12 years.
The "sadistic exploitation" conducted by Robert Hunter, from Middlesbrough, was so extensive that an international operation through Interpol was sparked.
Teesside Crown Court heard the 35-year-old had used sites such as Facebook, Skype and MSN to abuse girls as young as nine from across Europe, Asia, Canada and America.
He often posed as the singer Justin Bieber in an attempt to convince the girls to expose themselves and perform sex acts on webcam.
Hunter was arrested in December 2012 but continued to target children while on bail, which resulted in a girl from Tasmania contacting police who traced him to his home.
Some 800 pornographic videos and images were discovered on his computer.
Prosecutors said: "Over the course of 2010, 2011 and 2012, Hunter, using a number of online aliases, had pretended to a number of very young girls that he was a teenager.
"On each occasion he was able to disguise his true age and identity by the clever use of images of young boys or by pretending that his computer wasn't working properly.
"As a further demonstration of the naivete and innocence of his victims, he was also able to persuade some that he was the music artist Justin Bieber.
"He did this in order to dupe and encourage these young girls to strip on webcams and perform sex acts for him."
Hunter also blackmailed some of the victims into agreeing to his demands by threatening to make the videos he had already made of them public.
Defending Hunter, Tamara Pawson said he was remorseful for his actions and the distress he had caused.
Hunter pleaded guilty to 30 offences, which included 15 charges of causing or inciting a child to engage in sexual activity and 14 of making indecent photos of children.
