An HIV-positive former Mountie has been sentenced to just over three years in prison for sexually assaulting a 14-year-old boy and distributing child porn that detectives described as some of the worst they'd ever seen.

Warren Robert Allen, 53, was arrested in 2010 after he sent an undercover officer 6,700 graphic images of children -- including infants -- being sexually assaulted and tortured by adult men. After police searched Allen's Vancouver home and examined his computer, they also discovered evidence that he had lured a teen boy to his home to have unprotected sex with him and another HIV-positive man.

Crown prosecutors had asked for Allen to serve as long as six years for the sexual assault and up to four years for the child porn charges, with both sentences to be served consecutively. But in a decision B.C. Supreme Court Justice Sunni Stromberg Stein ruled that shorter sentences of two years for possession of child pornography and 18 months for sexual assault would be more appropriate. She also gave Allen three months' credit for time served.

The judge also declined to issue an order banning Allen from places like parks and schoolyards, saying that it would prevent him from walking his dog.

Police believe that Allen was part of a massive, worldwide child pornography ring broken up in 2010 after an investigation that began with officers in Toronto. The so-called Project Sanctuary probe stretched across Canada and into the U.S., U.K. and Germany.

Investigators found more than 840,000 images on Allen's computer, according to court documents. A full forensic analysis has not been completed, but of 200,000 images viewed by police so far, 27,000 featured children younger than five.

Vancouver police told the court that nearly three-quarters of the images and videos can be classified as "extreme" child pornography, and an experienced officer said that at least one of the videos was the worst he'd ever seen. The images described in court documents are deeply disturbing and feature very young children bound with duct tape or wire while they are abused.

Investigators also discovered online chat records that showed Allen bragging about "tag-teaming" the 14-year-old boy after giving him drugs. He also chatted about spending the past 20 years trying to infect as many unsuspecting men as possible with HIV and described an urge to make his own child porn because he could never find material that was "brutal enough."

In court, Allen blamed his child pornography fixation and interest in young boys on an addiction to crystal meth. He had been clean for three months by the time of his sentencing on Jan. 20.

Allen served with the RCMP for six years beginning when he was 20 before leaving to obtain a law degree. He never practiced as a lawyer.