An Edmonton pedophile with a child-porn addiction was designated a long-term offender Friday and sentenced to 4-1/2 years in prison to be followed by a decade of close supervision in the community.

Dwain Robert Becker, 46, had pleaded guilty to possession of child pornography, sharing child pornography over the Internet and breaching court orders. Lawyers had suggested that Becker should be under close supervision for six years after his jail sentence, but provincial court Judge Lloyd Malin said public safety demanded a decade of supervision.

"No treatment or tool exists that will completely rehabilitate Mr. Becker," Malin said.

In 2007, Becker was convicted of importing and exporting child pornography and sentenced to four years in prison. He was released in May 2011 under strict conditions.

Months later, in August, Becker was visited by a social worker who found lists of email addresses and addresses for pornographic websites. Becker said he had written them down from memory, as he was not allowed to access the Internet. The social worker turned the lists over to police.

When police visited a week later, they found a cellphone with Internet access, which Becker was not allowed to possess because of the conditions of his release. He admitted using the phone to contact boys seven to 14 years old in chat rooms and downloading child pornography.

Becker told police he began "to fall off the rails" and indulged his addiction to child pornography. Investigators found 210 child-porn images on the phone. A further 662 photos of boys in various states of undress were found. Becker had sent some images to various email addresses.

Court heard that Becker is a high-risk to reoffend.

Becker, a pale and balding man, told court he is willing to submit to chemical castration and did not fight his long-term offender designation.

During his decade of supervision, after his prison sentence, Becker must reside at a halfway house, take sex-offender counselling, take medication as prescribed, stay off the Internet, avoid contact with anyone under 18, stay 100 metres away from places where children gather and submit himself to searches at any time.