A Mount Pearl man who said he is addicted to child pornography has pleaded guilty in a disturbing case involving images of children being abused and sexual encounters with boys.

Craig St. John pleaded guilty to trafficking and possessing child pornography and to having sexual encounters with young boys over the internet.

In provincial court in St. John's on Tuesday, St. John kept his face hidden behind his long hair and beard as his crimes were read into the court record.

St. John was arrested in 2010 after police in Saskatoon, Sask. noticed someone frequently using an online file-sharing service to distribute child pornography. They traced the computer to an address in Mount Pearl, and contacted Sgt. Ed Billard with the Royal Newfoundland Constabulary's child exploitation unit.

When police seized St. John's laptop, it contained more than 12,000 images of child pornography and 1,100 child porn videos.

Later that day, St. John gave a statement to police in which he admitted to trafficking child pornography.  He said the images were "like a drug to him."

RNC Const. Greg Hobbs testified that the material was vile and disgusting.  It included images of man having anal sex with an infant, and of young children forced to perform oral sex on adult men.

St. John preyed on boys online

But while police analyzed the massive amount of child porn, St John acquired a second laptop, and rebuilt his collection.

Only this time, he went further.

In 2011, police in Dorset in the United Kingdom received a complaint from a 14-year-old boy, who said he had met a stranger on a website for gay or confused teens.

The person claimed to be another teenager.  In fact, it was St. John.

He sent the boy images of child porn, and convinced him to remove his clothes and masturbate in front of a webcam.

Police again followed the online trail to the same home in Mount Pearl.

On St. John's new laptop, they found records of dozens of similar encounters with teenagers that all followed the same pattern.

Prosecutor Lloyd Strickland asked that St. John be sentenced to 42 months in prison. The defence is seeking two-and-a-half years.  Defence lawyer Randy Pearcey noted that St. John has co-operated with police, including handing over his online account alias, so police can use it to catch other child pornographers.

St. John will be sentenced on July 13.