South Shields pervert incited young girl to take naked photos of her little sister
Kristian Lewis, who was already a sex offender, used a secret phone, which he kept hidden from authorities who checked up on him, to set up a social media profile where he posed as a 15-year-old boy.
Newcastle Crown Court heard the 36-year-old sent 10,000 messages under the fake name and over a period of just eight days had contacted 24 young children, who he engaged in explicit, sexual chat while trying to convince them to take naked photographs to send to him.
A judge said there is "likely to by many more" youngsters who were spoken to by Lewis, who was already banned from having any contact with children under the terms of a sexual harm prevention order.
Lewis, formerly of South Shields, was collared when police in Minnesota, USA, received a report from a worried mum who showed detectives a chatlog, from messenger site Kik, between her eight-year-old daughter and a UK stranger.
Prosecutor Michael Bunch told the court: "In the conversation, the defendant incited her to take indecent images of her four-year-old sister, who was asleep in the same bedroom at the time.
"In the chat, he also tried to get her to take pictures of herself and engage in sexual activity with her younger sister."
Lewis had said to the youngster in one message "come on, let me see you two doing it".
The court heard US detectives were able to trace the IP address of the sender who set up the account that had sent the messages to the little girl.
The information was then sent to Northumbria Police, who found a phone, that Lewis had not declared to his risk management officer, hidden in a wardrobe.
Two indecent pictures of the four-year-old, taken by her sister, were recovered from the device.
He had also kept a "clean" phone, which he did declare to the authorities and would hand over for inspection, as required by the terms of a sexual harm prevention order imposed in 2015.
The order had been imposed as part of a suspended sentence, for having indecent images of children.
Lewis, now of Tynedale Drive, Blyth, admitted two offences of breach of a sexual harm prevention order, inciting a child to engage in sexual activity and making indecent photos of children.
Judge Edward Bindloss sentenced Lewis to five years and three months behind bars and said he must sign the sex offenders' register and abide by a sexual harm prevention order for life.
The judge told him: "The US authorities tracked what had happened, they investigated it, traced it to your IP address and informed the British police, who came and found the phone and exposed what had been going on."
Judge Bindloss said Lewis poses a "high risk of serious harm to children".
Kate Barnes, defending, said Lewis had initially complied with the orders made in 2015 but reverted to his previous, illegal, conduct after his relationship broke down and he moved out of the family home.
Miss Barnes said Lewis had been drinking to excess and added: "He struggles to explain his conduct."